Advice
You get out of it what you put in. I intentionally made friends with people so that if I ever need a shift covered, I had people I could ask. I returned the favor as well. Additionally, smiling at grumpy customers can go a long way. Especially if you want them to fill out the survey at the bottom of the receipt. By being nice, I was able to convince people to mention me positively in the survey, and I was rewarded with coupons for money off my purchase!