Working in the food service industry

I am going to state the obvious here, but people can be so insufferable especially to food-service workers. It never fails to boggle my mind how self-centered and impatient customers can be with me and my fellow employees. It saddens me, to be honest, more than anything that people have become increasingly more this way and it seems that there is no reversing it. It definitely has to do with the state of things. I'm no expert but times are tough for people abroad more so and people just want to have a good time I am responsible for giving that good time but investing so much in such a fleeting moment is a little unrealistic. I do always try my best but I am not a robot. It feels like a lot of pressure sometimes. Some things have been happening recently that have made me feel bad and I just end up crying in private about it. One has been little comments that get under my skin like someone today who said, "having short-term memory issues this morning?" like I wasn't trying my best. I would never say that to anyone, ever. The context is I forgot to put in her food order a few seconds after putting in her coffee... that's it. It was 7:30 in the morning, mind you. Secondly, a man said, "why didn't you offer to let me have a table?" when he specifically ordered to-go and I told him to-go was not for sitting down at a table. He then proceeds to BLAME ME for his misunderstanding... fun times, guys. One more thing and I will stop this rant. A woman cursed out my boss today because I rung her order in wrong. Now, I get this, but cursing someone out over food??? I still can't understand that. My boss had no hand in the mistake. The fault was mine. I'd prefer her to curse me out than someone innocent. The worst thing about it was, she was so sweet to me during the transaction/order. I don't know what to think about people anymore. I just do my job the best I can, shut my mouth, and go home. Don't get me wrong though, I have thought about walking out before.