I write this for devs who port to Mac and tend to make programs that have Windows shortcuts as their defaults because many of these are counter-intuitive on Mac. It’s quite universal that these are used and it’s only most egregious offenders that don’t (Word):
redo: command-shift-z
Mountain Lion style fullscreen: command-shift-f
I’ll post more if I think of them. I know this is ■■■■ but it’s really annoying thinking that a program behaves like all rest only to find out it doesn’t and command-Y is a lot harder to hit than command-shift-z