The initial phase of being in love or going through a breakup, I can't concentrate and my work suffers. When a relationship is working, it has a positive influence on my well-being and that in turn positively affects my creativity and productivity.
Startup and teardown are expensive, but once you're past that, you're in the butter-zone.
[edit: by gang-bang, I meant group-sex. (I'm not understanding the down-votes)]