When one guy sees another walking down the street w/ an ill concealed boner, the following ?????? steps occur:
1. Guy 1 sees the unfortunate boner
2. Guy 1 thinks about why Guy 2 might have this boner
3. Guy 1 thinks about the things that might make this happen to him, too
4. Guy 1 stubbles across an arousing memory or idea
5. Wham-o, sympathy boner.