Both and neither. I started off with a Horde character, because the guy introducing me to WoW played on the Horde side. I got bored in the Barrens, made another character (this one on the Alliance side) and spent a good few weeks raiding before TBC came out. Stopped playing a few weeks after the Ulduar patch in WotLK, got convinced by my friends to start playing again a week before the Cataclysm, this time as Horde, so I did. Eventually realized why I stopped playing earlier on and quit once more. Haven't played it since February/March.
I love the Warcraft universe and it's characters, but the tedious daily grind I could do without... And a lot of people who went for the daily heroic instance were bastards. They would complain and still be the worst member of the group, and if called out on it they would start throwing insults... '-_-