Ye Olde Mirror Effect!

I use a Mac normally. I have to go back to Windows from time to time. After Mac OS X Lion reverse-scrolling, switching between Mac and Windows became a pain. I started to use AutoHotKey on my Windows machines to simulate the reverse-scrolling from Lion. All was well. Until I remoted from one of my Windows machines into another Windows machine which also had AutoHotKey installed with reverse-scroll script enabled. Guess what, it went back to the original scroll direction. I couldn't figure out for a while what was happening, until I suddenly realized what had happened. I couldn't stop laughing at myself for a long time :)

(Of course the solution was to suspend AHK on the target machine when I was remoted in)