Yes, it really annoys me too when people walk out in the middle of a movie. I certainly understand why you left ROTS, though. As much as I appreciate it when a director tries to capture the audience and make them interested in the film by opening with a fun scene (Bond, LotR for instance), a 30 minute sequence that tells us nothing we didn't know before and that's so full of superficial, bland, and sometimes embarassing stuff can certainly bore you out of the theatre. A problem with ROTS is that it's so unbalanced. You have a 30 minutes OPENER (sorry, I still don't believe it), then an hour of slooow, dry "plot" and "character" "development", an occasional death here and there, and then you got an hour of relentless duelling.