:-) I'm just going to add to this and share my stories for whoever may be interested on the topic!
A while back a group of English teachers went to a karaoke bar. The woman collecting the money just said to me, "This $10 is for you and Mike. He can pay you back." Ok, I didn't have a choice in the matter. Down to the last few days of me ever seeing Mike again. Mind you he had over 2 weeks to return to me $5! Finally, we're all out again and he goes to pick up $5 drinks at this corner bar spot for a group of us. All I remember is some how ending up with him at that bar and saying, "Hey Matt, you can give me back the $5 you owe me by buying my drink!" He literally said or had this, "Really?" look on his face! Yes, I f-ing want my $5 back! We're the same damn age and you're not any more entitled to my $5 than I am because it's MY friggin $5! LOL I know this is a big crap over $5 but it makes it that much more significant. That he feels he can just take my $5 because he doesn't know me well or will ever see me, again!
On the flip side to that. I was traveling alone in Hong Kong and met this British couple at the Peak. We chatted, took pictures for each other and even exchanged FB names! They eventually invited me to have dinner with them, so I went. When the bill came I made sure I had the servers tell me exactly what they're charging us for because it was in Chinese and I speak but don't read it. The man paid for everything and said I'm his guest he's treating me, etc. etc. I said, "No, it's fine." Eventually after at least saying no more than 2xs he laughed about it and took my money saying, "Ok, fine. This can go towards our cab ride!" I can tell his wife and I both were just relieved. I am just not one of those people and the bill portion was definitely at least $40, so I practice what I preach! :-) I would have never saw them again and I knew that.