If you're going to laugh at all the parts you find hilariously funny you should definitely use your most annoying, fake and pretentious laugh. It's not infuriating at all when you're getting into a moderately emotional, sort of well done scene and have someone laughing obnoxiously loud behind you, but you obviously know that.
Just sayin', you probably weren't the only person who found the movie cheesy and funny at times but you really don't need to let everyone in the whole theatre know by basically screaming your thoughts outloud.
PS: you were right there was no ending music and we all heard you the first time you said it. Great observational skills.