Badly Behaved

I am feeling badly that I behaved so poorly at Safeway today. I was no different than any other impatient, frustrated, annoyed customer, but I have really tried to not do that any more and to focus on being nice and staying positive. But Safeway just hits my button and I turned into an unpleasant person. I know I am not imagining it as the person behind me was staring at me while in line, thinking I was a rude jerk. OK, I was. So, I don't really do it often, and thought maybe I could go apologize to the checker and bagger. And at least I wasn't on my cell phone while behaving badly. But, my conclusion is that it is probably better just not to repeat my behavior and NOT to shop at Safeway, which triggers my rude behavior in the first place.