Murray's Law
Murray's Law states that everybody is happier when they are receiving sex on a somewhat regular basis. Food tastes better, work is easier, etc. when people are getting sex on at least a somewhat regular basis. Murray's Law can apply to people in relationships or people not in relationships.
Joe: Why has John been so happy lately?
Dave: He's been getting some every night this week. Murray's Law, dude.
Dave: He's been getting some every night this week. Murray's Law, dude.