My mother told me to not care what other people thought. She also told me that words can't really hurt people ("sticks and stones..."). She also believed its "mean" to have any preference about people, calling it a version of "keeping score". In fact, "keeping score" was one of the worst things you could be accused of in my household. Her advice fails to accept the reality of social and emotional needs. It also fails…
To be fair to your mother, this particular advice and view was rampant when I grew up in the 80s/90s. My experience was that this is quite backwards. Physical altercations at school didn't hurt that much, but the name calling, social shunning and constant verbal put down was very painful and has affected my whole life.
Never say anything that couldn’t stand as the last thing you say to someone. You’re words matter more than you realize.