People who drive onto a garage forecourt and park up at a petrol pump. So you park up behind them and wait while they top up.
They then go into the shop, pay and return to their car. But rather than getting in and buggering off, they go to the boot, dig out a shopping bag and return to the bloody shop again!
5 minutes later they come back with a bagful of stuff, which they put in the boot. They then get in the car and spend another minute or two pissing about before finally FINALLY doing one!
Why oh why couldn't they have just parked in the allocated parking bay next to the shop rather than just creating queues at the pump, the clueless tossers!