There's a guy who is one of the technical managers in my company who is Bulgarian. He's one of the nicest, hard working and straight up guys i've ever met, as well as being very technical and massively interested in gadgets. We both have kids the same age, so we chat quite a bit while he is visiting our site.
He often goes to car boot sales, looking for parts for projects and stuff he can fix up, and at the last one he went to he saw a guy selling old mobile phones. The guy was selling a phone that he recognised as a collectible , and the guy was selling it about 6 times cheaper than you'd get for it on ebay.
He didn't have enough cash on him to buy it, so he kindly gave the guy the tip off and suggested he stick it on ebay. The guy thanked him with ' why don't you sell it yourself, then you can buy a fucking ticket home'.
I just seriously don't understand how you could be that rude to another human being you don't know.
Everything else goes though and I do mean everything, both ways. Hilarity always ensues.
The relationships where you can take the piss are always the best, whether it's race, age, height whatever. When you know someone well enough to call them anything, because you know that they know your joking.... That's pure harmony