Interestingly enough, I had six dungeon runs so far - the three beginner dungeons, once in beta 3, once after launch. And all six groups were friendly, professional and the only time one of my groups wiped was in beta 3 because that was the only way to reset a bugged-out encounter

The tanks tanked, the healers healed, the DPS followed target assignments, crowd control was applied, people congratulated each other on loot and said thank you and goodbye at the end.
I wonder how long my lucky streak will last.