There's nothing more annoying than being out questing with someone far away from a team up kiosk and coming up on a raid fight and trying to team up and you and your friend get taken separately then you have to wait 10 mins to try again and people will usually abandon the team. i think there should be a way to join team up with a group kinda like how you join a tournament or at least being able to see how many people are currently in a team up.
That reminds me of that long dungeon over in Dragonspyre with the ghost dragon at the top. If you leave before the person you're helping fully completes the quest, you have to wait around 10 minutes. It happened to me once and I got really mad. I enjoy helping people out in the annoying Dragonspyre fights and dungeons. This just makes me not want to help.