Phantom2 - Quite often, if the show is bad enough, the cast know it and are not surprised or offended when people leave. Also in shows that are intedended for more mature audiences, people not knowing there may be adult themes and language will leave for those reasons as well. When I performed Corpus Christi, I was surprised how many people DIDN'T walk out. Actors may deserve respect, but so does the paying audience.
I only walked out of two professional productions. I left at intermission of the premiere of Civil War in Houston. I wanted to leave sooner, but I was not close enough to the aisle and I didn't want to be rude. I don't know what the theatre looked like during the second act as I saw droves of people heading for their cars during intermission.
I left after "Donna" during the 25th anniversary tour of Hair. The cast had the old-fashioned wired microphones on stands and kept tripping over the wires and knocking them over. The direction was horrible, the acting was horrible, the singing was horrible, the choreography was even worse. I was insulted that they charged as much as they did for such an awful production. I was seated on the aisle, but even if I wasn't, I would have walked out anyway. I was not being rude, I was being insulted. Luckily, they were not in Europe, or they probably would have been booed.
I should've left at the intermission of Notre Dame de Paris in London, but curiosity kept me there. It is the only show in during which I literally fell asleep. Had it been billed as a Cirque du Soleil pop concert, I probably would have known what to expect and not been as bored.
"What can you expect from a bunch of seitan worshippers?" - Reginald Tresilian