In this large and varied game of ours, there are many things to love. There are enough, in fact, that some of them seem downright odd to me. One of our paladins is absolutely smitten with achievements, of any kind. Every so often he'll suggest that we do something bizarre in a 5-man or a raid and I'll start to ask him why, and then realize, oh. It's for the achievement. But that's still fairly mainstream; lots of people like achievements for whatever reason.
Me, I like keeping my old weapons in the bank, lining them up in a nice row. I'd like to put them on a mantlepiece or something if they ever implement player housing. I really enjoy training new skills and recipes - the gold glimmer and "whoosh" sound are oddly satisfying. I like standing on things that can disappear (like mining nodes), making them disappear, and then sitting down or dancing on the empty air. These are all loves that have perplexed my guildies at one time or another. I also really like smelting.
Then there's my love for math of all kinds in this game, but that's not particularly odd. Plenty of people like to theorycraft. Right? Right?!
What are your WoW passions that nobody understands?