I've been using emacs every day all day every time I'm front of a computer, since 1991. I need only one finger to count the pieces of software I've been using that long that have never crashed or broken on me in any way.
I have also run into compatibility issues when using older versions of Emacs with newer packages, and newer Emacs versions with older packages.
[1]: I totally did not build my blog on top of a bunch of these quirks. Every time one of them is fixed I'm reminded of the workflow xkcd. https://m.xkcd.com/1172/