Many of the defaults are wrong.
- Toolbars suck
- Menus suck
- Having Emacs suspend the shell I'm working in sucks
- Getting names of files to actually appear as buffers, without extra gorp like a listener window that I don't care about at all is an exercise in frustration
... and more, but I need to find the last .emacs file that I spent half a day hacking up for details (and don't get me started on the geometry nonsense you need to control where Emacs starts up and how big its window is, and how well this plays with environments that have different monitor sizes and . . . oh bog, it can be better).
Inevitably someone's going to argue about how Emacs should be used ("you're supposed to get into it and never leave" and similar nonsense), or point out that I can customize away the things I hate. True. But I've been using Emacs since 1979 or so, and it just seems much worse in the last ten years.