WoW was my first MMO, and when I started playing six years ago, I was terrified of everything that wasn't "kill 10 boars." Dungeons? I'd run them with a friend, but it took some coaxing. Raiding? No way. It seemed way too complicated, not to mention having an audience anytime I noobed it up. PVP? That just didn't seem like something that would interest me all.
If I'd kept that attitude, I can't imagine I'd still be playing WoW, although Cataclysm's linear, quest-driven nature might have pulled me back in. Today, dungeons are second nature to me, just like they are to any other MMO player. I finally tried raiding during The Burning Crusade at the prodding of my guildmates, who needed a healer. After the very first night, I completely forgot what I'd been so nervous about.
As for PVP, I now have a level 85 warlock whose sole purpose is melting fellow players' faces and am leveling a warrior completely through battlegrounds. I'm not sure why I didn't think I'd be interested in PVP, but I was wrong.
After years spent playing a game, it makes sense that all of these things are second nature, so it's easy to forget what it was like when everything was new. The fact that once upon a time both entering a raid and healing fellow players seemed overwhelming is kind of ridiculous to me now that I do it three nights a week.
What about WoW made you nervous at first or just didn't seem interesting? What made you try it? Did you change your mind?