I'm too much of a perfectionist about contributing to open source projects
I find it hard to contribute changes to open source projects, and in fact even the thought of trying to do so usually makes me shy away. There are a tangled bunch of reasons for why, but I've come to realize that a part of it is that I'm nervous about my work being perfect, or at least very good. Take a documentation change, for example.
If I'm going to make any public contribution of this nature, for example to make a correction to a manpage, I'm going to worry a great deal about how my writing reads. Does it flow well? Does it fit in? Have I written some clumsy, clunky sentences that are forever going to sit there as a stinker of a legacy, something I'll wind up wincing about every time I read the manpage myself? I write enough things here that don't quite work or that make me wince at the phrasing in retrospect, so it's very much a possibility and something I'm aware of.
Then there's the question of what I'm writing down. Do I actually understand the situation correctly and completely? If I'm writing about how to do something, have I picked the best way to do it, one that works effectively and is easy to do? What about backwards compatibility concerns, for example if this is different on older Linux kernels? Does the project even care about that, or do they want their documentation to only reflect the current state of affairs?
I'm not saying that I should throw half-baked, half-thought-out things at projects; that's clearly a bad idea itself. But many of these worries I wind up with are probably overblown. Maybe I don't get my writeup entirely complete on the first submission, and the existing people in the project have to point out stuff that I missed. That's probably okay. But there's this gnawing worry that it's not. I don't want to be an annoyance for open source projects and (potentially) incomplete work feels like it makes me into one.
There's also that making changes to a decent sized project feels like a terrifyingly large responsibility. After all, I could screw something up and create bugs or documentation problems or whatever, for a whole lot of people. It's much easier to just submit bug reports and make suggestions about fixes, which leaves the responsibility for the actual changes to someone else.
(Of course, submitting good changes is hard, too. It really is a surprisingly large amount of work to do it right. But that's another issue from being (overly) nervous about how good my work is, and in theory many projects are welcoming of incomplete or first-pass change submissions. I doubt I'll ever persuade myself to take them up on their offer, though.)