> The point of non-mandatory tipping though is that it feels good for both the sender and the receiver. It gives the sender the warm fuzzies for giving even a trivial amount, and the receiver gets a concrete demonstration that their efforts are appreciated.

Note, though, that for tipping systems where the tip is not cash or something reasonably equivalent to cash, the receiver might find the tip annoying.

For instance, I would overall be unhappy if someone on Reddit gave me Reddit Gold. Sure, I'd be flattered that they liked my comment enough to want to reward me, but I've looked at Gold and did not really see anything in it that I was interested in. I'd certainly get much less out of Gold than the giver thought I'd get, and I'd end up feeling that I had just wasted their gift, and I'd feel bad. I actually wish Reddit had an option one could set to disable the ability of one's account to be given Gold.