I find what happened to me the other day amusing. I was gonna use my Hearthstone to go to Dalaran, that's usually where I had my hearthstone set to and I was in the Trade District of Stormwind... so I'm sitting there waiting for my hearthstone to come off cooldown... and I click it.. and port like two feet from where I was.... I turned out I had my hearthstone set to the Inn in the Trade District.. all I could do was facepalm at myself. xD