When a customer comes into your shop, it means there's a good chance they will spend money on a service/good you provide. Bearing that in mind, why do some people feel the need to act superior or unwelcoming to a customer? You can bet your arse I wont be coming into your store or recommending you to anyone who want to fix their shoes.
Ultimately, you look like a miserable gimp and you lose money. Great thinking, no wonder you own a business.