I don’t care how cheap it is

Whenever there is clearance and the shoes are like 10$, some customers feel the need to buy every shoe in their size, doesn’t matter if it is 20 pair and the shoes are ugly as sin. Only to come back, many times the very next day, hauling all 20 pairs in a bag to return them and buy another 20 pair. This ritual will continuously be repeated until the customer has owned, at least once, every pair of shoes in there. I ask, Why? Why would one do that. To go through that trouble, is it a hobby? I just don’t understand.