The women that stand right in front of the only sink the work breakroom, chatting away when I have a cup to rinse out. There is an entire room of tables to sit and talk at, but you have to stand in front of the only sink. This annoys me everyday.
A variation on this is the people at HyVee who leave their cart parked on one side of the aisle while they stand there and look for something on the other side. Leave the cart on the side you are on rather than blocking the entire aisle. Please.