I've been to around 50 countries, been to Europe over a couple dozen times. Worked overseas. Helped setup offices and resellers in Belgium, Hungary, china etc.
I can't keep it straight.
I must be slow.
The best tour guide in the universe, Stephen McPhilemy, tells his origin story (his first tours) of becoming a tour guide in Ireland: first he is volunteered as someone who can speak French to be a tour guide of a French group (he doesn't speak French beyond a few words). No tips there by the way. And then he gets a second group of Americans. And at the end of tour, these American start putting money in his hand. And he's like "what is this?"
What is going on? But one after another, every person is putting cash into his hands. Were they asking for change? Did they need coins for the WC? He didn't get it.
He tells this story on a RS tour of Ireland. We are all laughing. And of course this being a RS tour, nobody tips him at the end of the tour.
A couple years later, my wife and I took a tour he did as his own company. He is the owner. He owns this new company. At the end of tour, sure enough my tour mates start tipping him. Big tips too. And my wife and I are the last ones to be dropped off. And I say "I am not supposed to tip you, right?" And he says "you don't have to tip me." And my wife is poking me to tip him. And I know if I don't tip him, I'll be the only one in group that doesn't tip him.
And this is the best guide in the universe. I am not kidding. He has a gift. Amazing talent. He'll make you sing. He'll make you laugh. He'll make you cry. You'll learn a ton too.
Anyway, I don't tip him. And he looks back at me with his eyes that seem to be saying "you cheap bastard."
So, yeah, I dunno.
Happy travels.