as I got myself into tighter and tighter jams
I suppose this is the thing; if you're happy to learn that way, fine. It's just that git is particularly prone to "I've trashed local state and lost work" / "I've just pushed a huge mess and will have to lose time cleaning it up, if that's even possible".
I don't think git should be prone to trashing local state due to how it usually yells at you when it's about to do that, but then I've been working with a student this quarter who seems to do that every time I push something to github and she needs to pull. I think if the git community got together, did a usability study on how people actually use git, and renamed/split out commands into names that made sense, it would be a huge boon for general usability.
Simplification! :) "git checkout file" reverts a file from the index. If it doesn't exist in the index, then from HEAD.
The problem is that you can make a typo, because branches, tags and files are all in the same namespace. Suppose you wanted to type "git checkout foob" which is a tag or branch, but instead you make a mistake and type "git checkout foom" which is the name of a file that happens to have unstaged changes. Oops!
If "file" has unstaged changes, then "git checkout file" should rename it out of the way first to "file.#1#" or whatever. (Hello, look at CVS!)
Learning by mistake is one of the quickest ways to learn something though. Personally, to mitigate the possibility of losing my hard work to this problem, I started using git for personal projects and didn't use it for my important work until I was comfortable with it (eg had run into several problems, but resolved all of them).
This also helped me understand Git well enough to teach it to my colleagues (and in teaching others, you learn even more yourself), and now that everyone on my team is comfortable with it we've switched to it almost exclusively.