For example, git's cli user interface is monstrous (yes, I know, you personally have 800 cli commands memorized and get them all right every time, that doesn't make it "good"). From the outset, the maintainers of git basically decided "it's too much work to make all the cli flags behave and interact consistently" so they didn't. This allowed git to grow fast, at the cost of the cli user experience.
That said, git is big enough that multiple companies have come along and "solved" the git UI problem. None of these aftermarket UI layers are perfect, but there are enough of them and they are different enough that you can probably find one that is good enough for you, along whatever axis you personally dislike the git UI (examples include [0], [1], [2], which tackle very different user workflow problems).