One of the many lessons that my father taught us growing up was:
Protect your reputation and your name. Your name is the best thing that you have. In doing that, be careful who you spend your time with. It doesn't matter if you hang out with "Sandy" because you think she's cool, if everyone knows that Sandy smokes pot all day, even if you don't, everyone thinks you do. It's called "Guilty by association". If "Kendall" is promiscuous, and she's your best friend, guess what signal that sends when your with her morning, noon, and night?
Not to be confused with allowing what others think of you to run your life. That wasn't the lesson at all. However, you need to guard your reputation with all that you have. Your legacy depends on it.
I am teaching this to my daughter. There are children that she likes, that I simply do not allow her to spend time with outside of social situations such as birthday parties, school functions, etc. When she asks why, I simply tell her:
They are not kind to their peers.
They are disrespectful to their mother.
I am thrilled that they are a straight "A" student, however, their academics are not what I'm concerned with. It's their name, their character, and their integrity that is going to define who they are, not their report card.
She gets it. I think at times she may even agree. She can hate me now, but she will thank me later. Right now, I have to protect my daughters name, until she is old and wise enough to do it for herself.