Putting my 2 cents in here
If its a FP I really really love (like the Foundry - I'm a KOTOR fan) I will sit there - on HM and watch as the bad-*** droid comes out - or as Revan is talking. I will NOT hit the spacebar if you are having a hissy-fit and can't take 2 minutes out of your time to watch something that I thoroughly enjoy. I remember one time I was with my tank friend and this guy was so rude about the whole thing we literally RP walked through the entire FP :P
That being said - I usually run with my friends (we are a TANK/HEALER/DPS) combo. We do have the common courtesy to let people know if we are not going to be skipping mobs, cutscenes, ect. Usually we'll say 'Hey - we're not spacebaring - if you'd like to leave nows the time'.