I've bitten my nails all my life.
(Well, and picked at them and tore them by hand; not always with my teeth.)
Once when I was in seventh grade or so we were supposed to write about a nervous habit we had, and I picked that for lack of any better ideas; but I didn't actually think of it as a particularly nervous habit. It was maybe mostly a fidget thing, something to keep my hands occupied; but it was also useful for getting stuff out from between my teeth if I didn't have a toothpick handy. And it kept my nails short.
And yet, all my life I have somehow thought of nail-biting as a moral failing.
Which is silly. It's no more a moral issue than, say, having an uncluttered desk is. But I've still had this lingering idea in the back of my head that biting my nails was in some way bad. Not a health issue, just something generally acknowledged as something that one Shouldn't Do.
None of which I really thought about consciously until a couple of weeks ago, when I realized that I hadn't bitten (or picked at) my nails in a couple of weeks, and was feeling no particular need to do so.
There've been a couple of times in the past when I've gone a week or two without nail-biting, when my nails have gotten long enough and distracting enough that I needed to get out the fingernail clippers. But that's always ended pretty quickly.
This time, I think it's been well over a month, and I'm finding it pretty easy to refrain.
I have no idea why. It wasn't at all a conscious decision at first; it just happened. It didn't coincide with any particular big changes in my life, or any particular reductions in stress or anxiety. (I might even be clenching my jaw a little more than I used to, which is probably worse for me.)
But now that it's happened, I'm gonna continue not-biting at least for a while, and see how it goes.
I keep comparing this in my head to my shift a couple years ago toward flossing regularly, but it's not really the same at all; that was an important dental-hygiene issue that has a real effect on my health, this is just a habit.
But I still think it's interesting to see how something habitual can just suddenly stop.