I love RStudio in general, but there are a couple of things that drive me crazy. I thought I'd open a thread for people to share their pet peeves (and maybe someone else will come along and explain why you've been doing it wrong all these years). Actually mine are all related to accidental keyboard shortcuts, and so I can disable these in the Tools menu...
Code folding - Alt+0 (when I meant to type Alt--). Suddenly all my code vanishes into little purple rectangles and I have to scratch around to figure out how to restore it (it's on the Edit menu, not the Code menu or View menu!).
Pane zoom - Ctrl-Shift-[1-9]. Suddenly one pane explodes to fill the screen and everything else disappears.
Zoom - Ctrl-- (when I meant to type Alt--). Suddenly everything is tiny.