When I first started in the business (Jeez, is it really fifteen years?) making games really was, well, a lot of fun and games.
There were, of course, plenty of creative frustrations and long hours, but back in those primitive days game development was just like what you want in a game: adventure, exploration, and immediacy. When I look back at the kinds of stuff I did in the Wild West days of games — like the Mechs in MechCommander, the Ospreys in Half-Life, or the animations in Counter-Strike — I remember it almost the way you do a great gaming session: a lot of drama, laughing, cursing, and pushing yourself hard.
In a word, fun.