Overall I love unity, but one thing that drives me insane is how many weird UI quirks they just don't fix, like how incredibly primitive editing arrays in the inspector is (its a nightmare to reorder anything) or dealing with asset imports that take forever. They take these huge projects on, the great rendering features and such, and theyre impressive, but somehow they won't fix small things that are seriously aggravating in day to day use.

Also while I do love c#, I think it was the wrong language choice, because you end up having to write code in a really constrained way to get around garbage collection issues. Its getting better, but for games id prefer a non gc language