Some of the first “life rules” I can remember being taught by my parents were that life isn’t fair, I am not going to be the center of the universe, and there is nothing preventing people from hurting my feelings.
If you’re offended by something, shrug it off, put on your big boy pants and move on.
Simple.
I've often thought about writing a children's book (elementary level) about life lessons. Hell maybe it'll even rhyme. There are too many children's books with happy endings, and all of the "life lessons" books are aimed at young teenagers who are already screwed up and on Xanax, who probably don't have "reading a self-help book" at the top of their priority list.
"Chapter 1: Getting suckerpunched isn't fun, pocket-sand KCHAA"
"Chapter 2: Your baseball glove didn't disappear, your neighbor stole it"
"Chapter 3: Your cat didn't run away, it is flattened in the road"
"Chapter 4: Why you don't actually want to grow up faster"
"Chapter 5: You had fewer Christmas presents because of alcoholism"
"Chapter 6: Self-deprecation as a confusing defense mechanism to insults and criticism 101"
"Chapter 7: Avoiding people with trenchcoats"
You know, stuff like that... Every 5 year old should know.