I think that at a gut level, there are certain things that I believe don't take any time.
Pleasure reading, for example. If I spend five or ten minutes reading a few pages of a book, that doesn't count as time spent. If I have x minutes left in which to do something, then I “know” that I can read for five minutes and still (in my mind) have x minutes left. (I'm talking about the amount of time I expect beforehand that something will take. After I've done that five minutes of reading, of course, I can look at the clock and see that in fact it did take time. It's just before and during the reading that I'm operating under the mistaken belief that no appreciable time will pass.)
Also, somewhat relatedly, if a process takes x minutes, then starting it five or ten minutes late for any reason (not just reading) doesn't count as starting it late; it'll still (I subconsciously believe) fit into the original time window. For example: It normally takes about half an hour for me to get shaved and showered and dressed and get to work, so half an hour before a work meeting I need to get started on that process; but if whatever I'm doing beforehand goes a few minutes over, that's not a problem—at some deep level, I seem to believe that the process will automatically and magically still fit into the available time, without my having to hurry.
Speaking of things going over: if I'm almost done with something, then I know that finishing it up will never take more than five to ten minutes. (Which doesn't really count as going over.) No matter how many times finishing something up takes me fifteen or twenty minutes, or an hour, I continue to be sure in any given instance that the amount of time finishing-up will take is five to ten minutes.
I mentioned that pleasure reading won't take any time. Another thing that won't take any time is blogging. I can type up a quick blog entry in no time at all. I'm sure of it.
I do know that TV takes time: 45 minutes for an hour-long episode on TiVo, skipping all the commercials. Rewinding to watch bits again won't take any time, though; nor will deciding to watch one or two of the commercials after all because they look entertaining or because they're previews of a forthcoming movie or ads for a ballot proposition. Nor will pausing to go to the bathroom or get a snack.
Movies definitely take time. However, watching DVD extras won't take any time. I can start watching a 90-minute-long movie on DVD at midnight, and then watch several deleted scenes and a making-of segment, and still be in bed by 1:30 a.m. (Preparing for bed also won't take any time.)
Car travel is tricky. Travel certainly takes time, but traffic won't cause delays. And travel only takes the amount of time that I'm sure it takes. I got from my place to a particular spot on University Ave in Berkeley in 45 minutes once, years ago, and ever since then that's been how long I know it will take to get to Berkeley. Regardless of where in Berkeley I'm going, or how heavy traffic is, or the fact that getting to that same spot on University usually takes an hour.
And travel lateness is further exacerbated by the abovementioned fact that starting something five or ten minutes late doesn't change the expected ending time. So if I'm supposed to be in Berkeley at 2:00, then I should leave home by 1:15; but if I actually leave home by 1:25, I can still get there by 2 without hurrying. (That certainty tends to last only until I'm in the car; during the trip itself, I'm very aware that I'm running late, especially if anything happens—like traffic, or needing gas—that's not my fault. Well, y'know, not my fault except for the fact that I totally failed to take the strong likelihood of it into account.)
Related to all this is that even if I don't have a fixed idea of how long a given thing takes, my time estimates are, shall we say, optimistic. If I guess that it'll take 15-20 minutes to do something, then in my head that becomes a belief that it'll take 15 minutes. (Again, even if I start five minutes late.)
Transitions between things, btw, also take no time. Saying goodbye at a party, for example? Instantaneous. Leaving work (including checking my calendar for the next day, shutting down my computer, getting on my bike gear, walking outside, and unlocking my bike)? Likewise instantaneous.
For some common tasks, like reading submissions, I have a reasonably accurate time sense. For example, I know that I can get through roughly four to six 4000-word stories in an hour (depending on how much skimming I do, mostly). But writing up my summaries and comments on a given story will take, I'm sure, no time at all. And the little interstitial things that I sometimes do between or during stories—looking up unfamiliar words, checking to see whether I'm right in thinking the author has some basic concept wrong, getting something to drink, taking a quick break to check email--will also take no time.
Playing an hour's worth of Dance Dance Revolution takes about an hour (even if I take a break in the middle). But showering afterward doesn't take any time.
In most contexts, five to ten minutes is kind of a magic number. I'm pretty consistently five to ten minutes late for things. (I've gotten much better about that over the past few years, but it's still quite often true.) (And there are contexts in which I'm often an hour or more late, but not many; that's mostly situations where there wasn't a specified time to be there, like a party, and the “lateness” is only relative to the time I intended to arrive.) In many contexts, being five to ten minutes late is entirely socially acceptable, so it passes without comment. It would seem to suggest that if I could reset my internal expectations and clock—aim to arrive at, say, 1:50 instead of 2—then I would always be on time. But that doesn't work for me very well; I'm too aware that I'm doing it.
Also, I hate waiting, so the idea of aiming to be somewhere significantly early and then having to sit around and wait for it to start feels like a waste of time to me. The fact that my lateness causes other people to have to sit around waiting is somehow hard for me to grasp, despite my usual tendency to focus on other people's needs.
There was a period, years ago, when I kept my clocks at home set five minutes fast. But I knew they were five minutes fast, so I took that into account in calculating times. Once or twice, a clock has drifted to be a few minutes faster than I know it is; but then I start noticing that travel is taking less time than I expect, and I figure out that my clock is fast. (And these days, when I'm checking the time I mostly use my iPhone, which picks up its time from AT&T, or my computer, which picks up its time from a central time server.)
That reminds me of another factor, one that I'm having a hard time articulating: I sometimes think of time in terms of quarter-hours on an analog clock face. This sometimes actually helps me be punctual; for example, if a movie starts at 8:05, then I know arriving at 8 is too late, so stepping one Discrete Time Unit earlier means I'll aim to arrive at 7:45, and will actually arrive at 7:55, which usually is just enough time to park and get tickets and find seats before the movie starts. But more often, it goes the other way: showing up at the train station at 7:45 would mean waiting for twenty minutes for the 8:05 train, which is a long time to wait, so instead I take one DTU step forward and aim to arrive at the station at 8:00, which means I get there at 8:05 and barely manage to get a ticket (or sometimes I get there at 8:10 and miss the train).
(The size of a DTU is situation-dependent; in some contexts, a DTU is half an hour, while in others, it's five minutes.)
Oh, and various aspects of my lateness only get worse when I'm hanging out with someone else who also tends to be slow and/or late, because I feel bad about nagging or pushing them to get moving, so I think to myself “They'll probably be done and ready to go in five or ten minutes, which doesn't count as late, so I won't say anything.” And then twenty minutes later the fact that we still haven't left yet is stressing me out so much that I can't think of a gentle way to point out the time.
I've gotten a lot better about calling ahead to let people know I'll be late; if I'm leaving home ten or more minutes late, and/or if it looks like traffic is going to be heavy, I'll often call. But I'm embarrassed to be late yet again, so I play down the degree to which I'm going to be late. “I'm going to be a couple minutes late,” I might say. I think somewhere in my head that resets the on-time clock; if I tell someone I'm going to be ten minutes late, then I get an extra five-to-ten-minutes after that new target time.
This entry isn't intended to beat myself up over my bad habits in this area, nor to claim that I'll stop doing this. It's something I've been doing all my life; I am getting a little better about it, but I doubt I'll ever stop entirely. Friends have gotten used to it; I wince whenever someone tells me, “Oh, we didn't expect you on time, we figured you were on Jed time,” but I don't have anyone to blame for that but myself.
(Added in 2010: Oddly, two or three times in recent months friends have said things like “I know you're always punctual, so I got worried when you were late.” I'm always confused when people say things like that to me, because I think of myself as almost never punctual. I guess I really am getting slightly better about that, but only slightly.)
I do apologize regularly for being late. And I may as well take this opportunity to issue a general apology for it. Even though I'm aware of it, it's not intentional; I always start out with the best of intentions to be on time this time. But deeply held (incorrect) subconscious ideas about how time works are hard to break.
By the way, it didn't take me any time to write this entry.
(Actual elapsed time between opening new-entry page and finishing: 55 minutes. But I may've done a couple of other things during that time.)
(I wrote this in November of 2008, but for various reasons didn't post it until now; while I was at it, I added a few new bits and did some light editing, which of course also didn't take any time.)