We have had camping trips spoiled by noisy drunken adults and their music into the night. Try and find sites that describe themselves as quiet and specifically insist on no noise at night.Its sometimes possible on larger sites to find a corner away from people.
Places to avoid pitching your tent are near the paths and roadways where people will be moving around the site and returning to tents after a night out.
We went to a Caravan Club Campsite for this reason to find a Caravan Club Disco going onto the early hours held by the staff!