<human>: Provide a brief overview of the text.

I work at a kid's gym. I teach classes to kids ages 1-7 helping them work on things like balancing, tumbling, not beating each other up, etc. The biggest problem is keeping kids safe, and the biggest reason they get hurt is if they're not listening to or following directions. Which is the kids' fault. I cannot make kids obey me, as hard as I try.

Today a girl got hurt on a balance beam course because she refused my coworker's help when she offered. The mother, who couldn't hear her daughter refuse our help, got livid when she saw that her perfect little angel had been injured and started yelling at us about how unsafe what we were doing was and how "one kid down was too many". I felt bad that her daughter got hurt and certainly would like to be as safe as possible, but when I tried to tell her that her daughter refused our help, she wouldn't listen and was convinced that her daughter would have asked for help. Because everyone knows that children hate independence and never want to do anything by themselves. (It's funny because it's not true.)

Anyway, she basically said that I'm terrible at my job and tried to threaten me by saying she was thinking about not ever coming back, which I was not terribly affected by because I don't get paid enough to care about that and also I never wanted to see her again in my life. But now that I'm home and trying to go to sleep, all I can think about is this conversation, echoing over and over in my head. 

I'm sure anyone who has worked in customer service has been told they are bad at their job/terrible people. How do you get yourself to stop thinking about it and move on? I would like to sleep tonight. :C
<bot>: mothers who take their 4-year-olds to gym are overprotective, and I am oversensitive and will cry myself to sleep.