J.D. is mad at Dr. Casey and wants to talk to him. When he finds Dr. Casey, he realizes that he is suffering from OCD and keeps washing his hands as a result. J.D. feels sympathy for Dr. Casey and is no longer angry at him because he sees the anguish on his face.
Sol tells Max that the world cannot be easily solved with math, but Max disagrees. Sol then tells Max about his obsession and how his mind filters out everything else in order to find that which he is obsessed about. Sol gives the example of finding the number 216.
At Elaine's request, George purchases a "big salad" for her from Monk's. When his girlfriend appears to take credit for this, George becomes obsessed over the issue. His altruism is not pure: George derives utility from the fact that the purchase is associated with his generosity.