No more double-clicks
During a shower thought, I realized that I'm no longer double-clicking, for the most of my computer usage.What are double clicks useful for? Maximizing windows, opening files, starting apps, etc.
But I'm just not doing this stuff any more - window management is only a keyboard thingie with xmonad, maximizing windows on OS X is a single-click anyway, and on Windows I've moved to using the (single-click) buttons, too.
The other tasks are pretty much non-existent with xmonad (and no "desktop manager").
On OS X app starts only come via quicksilver/the dock; opening files can also be done using drag&drop and I'm increasingly doing this.