What does this Joke mean?

Omg this is so funny! I'd never heard it. Oh it's funny because the psychiatrist is telling the moms about their obsessions based on the kids names and the last one is Richard and people tend to call Richard's () so that's why the mom left because she already knew what the psychiatrist was going to say about her obsession. You get it!? Since the kids name is what do you think is her obsession....:)