This New Scientist article summarizing a new human behavior experiment goes a long way to explaining why men seem to get in trouble with their significant others all the damned time:

Psychologists in Canada have finally proved what women have long suspected - men really are irrational enough to risk entire kingdoms to catch sight of a beautiful face.

Somehow, though, I don't think an appeal to science will keep me from getting punched next time a short skirt walks by in the metro.