a need to seed

Why do I always feel an obligation to seed after downloading? People tell me I'm a sucker. They tell me I should bail the second I get my file and leave the seeding to people with T1/T3 connections. But I feel guilty doing that. Like right now, I'm seeding to just four people and I've got my upload speed maxed out. If I quit, their download time will go up and in my head I'll see their happy faces turn to sad faces.

Or maybe they're actually all asleep like I should be.