[Lust doesn't bear Al - or anyone, really - any ill will over what happened. It was an unfortunate incident, but no one's real fault.]

Fight or flight and attraction for mating purposes, of course. That's one thing.

But really think about how many things you feel in a single waking period. How the smallest irritation can ruin a mood for the rest of the day. How one minuscule slight from the right person can leave you hurting for weeks. How those feelings permeate everything and effect every single thought you have. Unhappiness of any sort drains the drive, effects thought and decision making, interferes with daily necessities...

One could argue that the removal of feelings leaves nothing but intelligence - pure logic without emotional bias.