I was a Linux sysadmin and was quitting my job to go to college. I had been using Linux on the desktop since 1995. I thought I'd buy a laptop, and why waste my time trying to worry about hardware compatibility with Linux when I already have a Linux desktop?
I figured, "let me just buy a Windows machine so I can easily play DVDs and use Office". When I stepped back and realized that was my only criteria, I thought, "why not try a Mac?"
I brought my white G3 600mhz iBook to (2002 tech company) work shortly before starting school, expecting people to make fun of me for buying a Mac ("everyone" used Linux, but Windows was begrudgingly tolerated in the community) and EVERYONE was interested in OS X.
I used that iBook for tons of work stuff in my last couple of months. Popping a serial console on SunFire 6800s, directly connecting via ethernet to them and forwarding X Apps to the Mac, etc. It was a revelation.
Not only that, but you could actually close the lid, put it to sleep, and the battery wouldn't be dead when you came back from lunch.