I keep on repeating something told to me by an American...

I keep on repeating something told to me by an American psychologist: "When you are making a joke about someone and you are the only one to laugh, it is not a joke. It is a joke only for yourself." If people are making a joke they have the right to laugh at me but I will ignore them. Ignoring doesn't mean that you don't understand. You understand it so much that you don't want to react.