Sightseers (2013)

Sheltered woman gets a boyfriend and accepts his invitation to go on a caravan roadtrip. We see a glimpse of trouble when he cannot let another tourist's littering go, but that's nothing. Soon they're on a murder spree, knocking off anyone who annoys them.

Wow, I'm making this sound almost good -- don't be fooled like I was. It's aggressively dull despite all the carnage.

F