This is why we fight

A friend asked me tonight if she could make her FB profile pic a picture of a cake.  "Sure," I replied.  "Why?"  She said it was so she could be reminded that people like to have their cake and eat it too.

Also tonight, a friend told me that my name had surfaced during a fight with someone.  About how I don't have a relationship with this person anymore.  What am I supposed to do or say about that?  I am 30 years old now, and I love being in my thirties and being an adult.  How do you tell someone that they are too immature to hang out with?  How do you explain that you don't want to be in a clique with people that you met 10 years ago, when you were a totally different person?  How do you explain to someone that you want to be surrounded by healthy people, not sick people?  Especially when they don't know that they are unhealthy.