How I Met Your Mother: 10 Legendary Barney Moments
7. Crazy Theories
Outside of his womanising, love of scotch and obsession with suits, Barney Stinson's next big trait is his constant need to fill the gang in on his many ridiculous theories and rules. Everyone remembers the Platinum Rule - "never ever love thy neighbour" - and the hysterical Lemon Law, but perhaps his funniest is the Hot/Crazy Scale.
During Season Three's fan favourite outing, "How I Met Everyone Else", Ted is shown dating a woman whose name he can't recall, so he just refers to her as "Blah Blah." It is here Barney introduces the rest of the gang and the fans to his Hot/Crazy Scale, which dictates that a person is allowed to be crazy as long as they are equally hot. He uses the scale to keep a track of Blah Blah's progress over the night, and its fun to see him play with the graph as she gets crazier and crazier.
Other theories and rules worth shout-outs include: "New is always better"; how to tell a girl's age based on their elbows; and that all world conflicts are based on sexual tension. The guy really is a visionary.