Yah up there you got free everything, free health care foremost on my mind
Down here as the saying goes "There is no such thing as a free meal." It's not directly offensive to just say "thanks" and take something like that from a coworker but leaves you at a disadvantage I think. Tough to explain. But that little barely-significant monetary compensation, or even buying them $5 worth of lunch or telling them "Go buy yourself lunch on me" when you try to hand them a bill kind of completes things; makes a definite end. There's no "disparity" afterwards; it's like an exchange of gifts. Like saying hello to somebody and them looking you in the eye and saying nothing back. They may not even take the money, try to give it back, but it's the attempt that counts.
I dunno it's wierd but that's the dynamic I've observed, it's pretty consistent too. Also, they know who to go to when something else like that crops up again lol
Sorry severely off-topic //straightens tie