Better To Give Or Recieve?

One day Tim was short a little for his daily holy water. He was with friends, however, and told them a little story in hopes they'd spot him some change.

"If you buy a guy a coffee, and he never buys for you, should you stop buying for him in the future?"

There was dissent among his friends, and they discussed the matter at length. Finally, they came to the consensus that it wasn't worth buying the guy coffee anymore; he was just a freeloader.

"If someone buys you coffee, then, are you beholden to that person? Is it out of duty that you would repay this person, or simply out of kindness that you return the favour?"

Again the friends debated, confused as all get out now. In the meantime, someone bought coffee and doughnuts for the lot of them and said, "Someone else has to buy next time!"