There was a nerdy chain e-mail comparing various operating systems to airlines (I don't remember all that many, because I'm not familiar with all the systems):
MS-DOS: everybody sits on the tarmac in rows of six, makes vroom-vroom noises, and pretends to be flying.
WINDOWS: a worldwide airline with service to practically everywhere. The only problem is that sometimes, for no discernible reason, the plane just explodes in mid-air.
LINUX: the tickets are free, no matter where you're going. You show up at the airport, and they give you a seat and a bag of nuts and bolts; you just have to get on the plane and screw your seat to the floor. You tell your friends how great it is, but all they can say is, "You had to do WHAT with your seat???"