People (sorry it usually women) who get their trolley at the supermarket, then go through the door and STOP about 2 feet inside, while they check their handbag/shopping list/hair/shoes/all the pretty things which are displayed. Thus stopping anyone else from entering the store.
While we are on it, what happens to women when they go shopping, they turn from normal rational human beings (insert comment here) into a sort of zombie who wanders round with a vacant expression repeating the mantra "pretty things, pretty things, pretty things" occasionally abandoning their trolley in the middle of the aisle to go and stare at some shiny wrappings.
To give you an idea of what I'm on about, imagine a huge shop with beautiful naked women on every shelf, then get a load of blokes with trolleys and watch them walk about. Trolleys everywhere, blokes staring open mouthed, etc. Now just take notice the next time you go shopping and tell me if the women shopping haven't got the same expression as those blokes in the nuddy woman superstore.
And in addition, just Women, snakes with tits the lot of them. They're just not wired up right.