I thought about outlook, too, but for the opposite reason: their web client overrides ctrl+r, making the way I force a refresh incongruous with the rest of the web.
Take Youtube for example.
If i scroll down to read some comments (yeah i know, i live dangerously for some reason that escapes me) and want to go quickly back up to the video, the natural reflex for me is to hit the home key.
But for some loony toons reason Google had decided to hijack the home key to mean "rewind video the 0 and start playing"!