Thank you goes pretty far. So does "I appreciate you doing xyz".

At least in the workplace. I have a lot of mutualistic and prosocial relationships. Somehow it's easier to be polite and distant and reciprocate favors in professional situations.

And when people go out of their way to acknowledge I helped or that the work was a pain in the ass, I feel appreciated. Even dumb things like someone bringing in donuts or snacks works on me.