So, I played in one of the Beta's before A Realm Reborn launch. I didn't do any research on any of the classes, partly because I was excited to play and partly because I thought the different roles would be obvious. So, I was playing as a marauder thinking it was a DPS class. I queued up for a dungeon blissfully unaware that I was supposed to be the tank.

Dungeon starts and everyone just stands there. I'm waiting for the tank to go so I could follow and they were waiting for me to go. So after about 2 mins of just standing there I finally ask "So, who is the tank". I got a bunch of lols a few wtfs and a few noobs thrown my way and everyone left. It wasn't until 2 months or so later that I learned marauder was a tank class. I had a good chuckle at myself.