Some friends and I go to a bar to have a few beers before dinner. Beer is expensive in Japan and so we order a couple of pitchers to save a few precious yen as opposed to bottles or individual pints.
We finish the beers, ask for the check, get it and leave some money on the table. It came to 4990 yen. We leave a 5000 yen note, thank the waiter and leave.
As we are an entire block away, we hear someone shouting behind us, and waving a piece of paper. We quickly realise it is the waiter from the bar.
He doesn't speak English, we don't speak Japanese but he had chased us out of the bar for an entire block to give us the 10 yen in change. This is worth around 0.06 (10c USD).
Tipping doesn't exist in Japan, or even simply leaving a tiny bit of change to save the waiter the hassle of getting you the change isn't a thing.
From there on in, I never tipped and waited for my change everywhere I went.
I was in Shenzhen, China, and a family stopped me and my wife and asked us (my friend interpreted) if they could have their children take a photo with us. They were visitors from the interior of the country, and had never seen an American before.
A similar thing happened in Shanghai. This time I was alone walking across the Waibaidu Bridge, and a group of teenage girls asked me (using sign language this time) if I could pose with them for a photo. I was happy to oblige, and I recall them all giggling as the photo was taken. (I wish I had a copy.)
Another surprise: I was in Pudong (the newly rebuilt area of Shanghai) and I couldn’t find the entrance to the subway (a two stop line between Pudong and the Bund). I approached a man who was walking near me, showed him the ticket I had for the ride, and he nodded vigorously. Then he indicated I should follow. We went about 4 blocks; he pointed to the entrance, smiled, turned and walked away. I had no time to offer him a tip, which (in retrospect) was a good thing because it might have been taken as an insult. I couldn’t believe that he had taken so much trouble for a stranger.
Again, similar experiences repeated themselves across China. The friendliness of the people, their courtesy, and their eagerness to help was wonderful. I don’t know if that classifies as “cultural shock” but it made me think about the US, and how I rarely experience such courtesy in my own country.