It's great it's been working for you so far, but I wouldn't continue laughing at customers if you're in the service industry. I had a friend that did this and thought he was so clever when he got away with it.

Well one lady absolutely lost her shit, took it offensively and made a huge scene in the store. When everyone's looking at you, the employee, and you're laughing, you 100% look like you're at fault. That dude got fired on the spot to save face in front of half the store.

What always worked for me when I worked sales jobs in highschool was agreeing with the customer. Shoes are too small? I agree, let me get you something bigger. Shoes are cheaper at another store? I agree, if it wasn't for my discount I'd shop there too, but here's a good deal on another pair. You're impatient and tired of waiting? I agree, I wish I could give every customer the time of day but this damn company works us like slaves!

Manager may not like it but they can't disagree when you're too sales every month.