Most visibly: Tab completion can get the wrong/unexpected file (note that it doesn't have to be the same filename to cause this problem...if I'm expecting "my<t

Most visibly: Tab completion can get the wrong/unexpected file (note that it doesn't have to be the same filename to cause this problem...if I'm expecting "my<tab>" to complete to "my program", because it is the only file starting with "my" but instead it completes to "My Documents" or requires a double tab and more specificity from me, that's an annoyance). Windows tab completion is perhaps the perfect storm of annoyance for me, with regard to case insensitivity. It'll complete to the first thing it sees case insensitively and then require cycling through all matches to find the desired file. This would also break file globs, or at least my expectation of what file globs should do. This is, of course, a mild bit of user hostility, but it is less friendly and harder to use, to me, than case sensitivity. As I noted above, it's mostly a matter of what you're used to, but in the absence of a reasonable case that case insensitivity makes life easier for users, the right implementation is the simpler one. The more dangerous stuff is where the OS decides that one file is actually a different file, through character conversion or through Unicode mapping. And, that, (not) coincidentally, is where serious security bugs were found in git. And, git is not alone in running into these problems. In short, I find it annoying that the OS would decide it knows what I want, when I ask for something else. But, more importantly, it has been proven occasionally to be dangerous, and often to be error-prone, in implementation. But, on that front, I'm probably just going to repeat what Linus said less effectively.