There's an unwritten rule in the MMO genre in general about pulling for Tanks.

1 - It's disrespectful. To the group and to the tank.
2 - It shows you're not a team player.
3 - If you can't be a decent human being and politely ask the Tank to either speed up or if they're hesitant to pull more, multiplayer games are something you should probably not be playing.

On my first run in a dungeon, I will not mass/chain pull for two reasons...

1 - I'm unfamiliar with the dungeon and I don't know what trash mobs do.
2 - I want to actually SEE the dungeon. I'll have plenty of time to ignore the scenery on my 2000+ runs that will be done down the road. I will appreciate the scenery my first time through (not excessively so, but enough that I can actually pan the camera around from time to time).