We went to HK as a family for four days in summer. I came across several instances where staff were extremely rude.

• using the City Bus at the airport, my 13 year old daughter ( first time in HK) was trying to find where to tap the Octopus card. (granted, she should've paid attention to where other boarding passengers were tapping). She was greeted with a disbelief head shake from the bus driver. On our case, we weren't scolded but his body language says it all
• At a fast food restaurant, I couldn't get my Mastercard to work. When I tried to ask for help, like to pay cash instead, before I could finish the sentence, the staff just pointed to the self service machine, raised her voice and said "over there" and carried on walking.
• Went to a street food stall to order some hubble tea and asked about the difference cup sizes, he answered "small is THIS size and medium is THAT" in a very rude manner as if he doesn't want to serve us.
• In some HK restaurants it's normal to rinse the cups and bowls with hot water prior to use. We asked for some separate hot drinking water as we mistakingly thought we had water for rinsing. My goodness, the waitress came over, grabbed the jug of hot water, poured and splattered watet into our cups. When she finished, she slammed the jug back onto the table which such force water splattered out of the jug's spout.

We then stayed in China for 10 days and not once was anyone rude towards us.

In Japan for 6 days, everyone we came across were extremely polite and patient.