Fight Club

The unnamed Narrator (Edward Norton) is a traveling automobile recall specialist who suffers from insomnia. When he is unsuccessful at receiving medical assistance for it, the admonishing doctor suggests he realize his relatively small amount of suffering by visiting a support group for testicular cancer victims. The group assumes that he, too, is affected like they are, and he spontaneously weeps into the nurturing arms of another man, finding a freedom from the catharsis that relieves his insomnia. He decides to participate in support groups of various kinds, always allowing the groups to assume that he suffers what they do. However, he begins to notice another impostor, Marla Singer (Helena Bonham Carter), whose presence reminds him that he is attending these groups dishonestly, and this disturbs his bliss. The two negotiate to avoid their attending the same groups, but, before going their separate ways, Marla gives him her phone number. Read more on Wikipedia.