I must have been fantastic back when I was working retail. I had effectively managerial powers when it came to day to day problems and returns. I was never comfortable issuing discounts unless I knew of them before hand. I had to get them signed off at the end of the day, but that took 10 seconds as I had the store mangers trust. In fact I was doing it so well, I assume it would freak out statistical analysis done on me since during the quiet times of the year I would do Negative sales over the whole day or near zero while everybody else was doing a couple of grand in sales. You would think I was stealing from the store in some sort of scam.
I was an anomaly though as few are willing to step up to the plate and enjoy the extra responsibility. The one thing I didn't do was sell the store credit card and I did get a talking to about it from the team leader. But I wasn't fussed about it. I have seen too many ridiculous store credit card bills to consider it ethical to push it. If you asked for it, I wouldn't stop you, but I would never, ever try to sell you on it.