You want work in a game? Try 7 days To Die. Clear a newly found town of 50 to 100 zombies so you can maybe find a can of dog food in one of the cupboards. That's work and it's fun and I have no idea why.
Killing zombies is always its own reward. :-) I guess they represent the perfect "Other", you can completely hate them and enjoy killing them without feeling any remorse or doubt.
