I think the tipping culture is different not only between countries but also regions of various countries.
I tip the curb side check in baggage handlers 10-20$ depending on the weather.
My husband and I cleaned our suite completely of garbage and washed all the dishes and utensils and pots and pans and left $50 as we never had them come in during our stay as it wasn’t practical with Maisey. She didn’t make a mess at all— I wiped her paws before we’d go back into the hotel and she definitely never had an accident. I feel like we probably should have left more. I generally abide by the $5 per day tip but in this instance with the dog, I still doubt myself.
20% for food delivery is basically our minimum. More if the weather conditions are awful. I figure if we can afford to splurge for someone else to bring us dinner then we should tip accordingly.
I over tip on Uber. In part because 99% of my trips are cheap (less than $12) and also to keep my rating up.
The difference between 15 and 20% as stated above doesn’t mean a lot to me but it means a lot to the person receiving it. And it pays off— the local, really good pizzeria had tons of yelp reviews that they take a long time to deliver. Same with the local sushi place. They always deliver well in advance of the expected delivery time.
I guess I view tipping as this/- if I don’t want to do it my self (whether self parking, driving myself, picking up food, going grocery shopping, etc) and have the economic means to pay someone else to do so, I should tip accordingly.