How does Collie embarrass and anger Helen at the pool?

Helen is surprised to learn that Collie has a date that night and is embarrassed when he suggests that she expects him to sit around and "moon" over her. He finally admits that the girl he is seeing is someone he knew long before he met Helen. Collie goes on to tell her that she doesn't know anything about him because she's never asked and she should realize that other people are interesting, too. He touches her chin and tells her that he is interesting; she might find him very interesting and she might find that he has a very important place in her life.