Parents and Teens
Why end the party at breakfast? My parties last until an hour after lunch.
Teenagers or tweens don't want their parents watching over them all night, it makes them uncomfortable (especially if they don't know the parent too well) and think they can't have fun and laugh so hard they cry.
Speaking from experience here. Parents also shouldn't plan the whole party (again talking about tween and teens) unless they are actual kids, 10-year-olds and younger.
The midnight snack should be an alone time between kids; no parent wants to watch kids play-fight over whether chips or popcorn is better. (it's definitely popcorn:).
Slumber parties should be a fun thing that is at least a third of the way parent free.