Ex roulette has 2 outcomes

1) Get a good team (about 30% of the time)
2) Get a decent team - a team that at least have done the instance and don't need babysitting
3) A baddie team - DPS who can't even reach 300 DPS to save their lives, and/or people who cannot/choose not to learn the proper mechanics on doing boss fights.

I'm still having nightmares of a SMN during Ex roulette who, after at least 6 wipes + my explanation on how to do the mechanics goes and says "I don't understand..."