I use git almost every hour and I rarely have to deal with git problems (just enough practice to avoid them). I'm also confident about resolving problems if they do arise. Heck, I even configure my entire system and manage my life using text files managed by git. So I don't claim that it's all that bad.

But if you want me to give concrete examples of how problematic git UI can be, you are so far removed from reality and are neglecting the very visible and vocal struggle git beginners have. I'm saying this as someone who trained a lot of people in using git from the very beginner level, all the way up to emailing patches - as part of a community and as a corporate trainer. I can write essays about every single problem that can trip a beginner due to git's inconsistency - but am not going to - because they are acknowledged problems (by git devs) and they actively work on it.