I'm going to buy stuff and return them if I don't like them
What makes you need to do that?
I don't want to keep something I don't like or will not use.
While getting a refund for a product you don't like or will not use isn't wrong, it is wrong to abuse a store's refund policy. That just will make it harder for future customers to get a refund.
I don't care about other customers. I don't want to hear that from you.
You should be more careful about buying things for yourself too, stores can ban from doing that if you overuse their system. Then you will be limited in where you can buy from.