Worst for me would be a tie between Aceh, Indonesia and Siberia, Russia. Both places seem to believe that the customer is always something to be avoided.
Best: Belgium-really nice, efficient service…and great food. Worst: Jamaica-most of the waitstaffs seemed to be high on ganja.
Best: Japan, restaurant workers there take their jobs very seriously and do them well, even in McDonalds, and no tipping.
Worst: France. I think if French wait staff were given the option of NOT serving tourists most would take it.
We noticed that in some places, too - it is quite efficient, I suppose, but it seems kind of like they’d like us to eat our damned food and get the hell out when they do that.
I have to agree on spotty Canadian service, too - when we’re booming here, there aren’t enough people to fill the service jobs, and restaurant service definitely suffers. In the height of the boom, restaurants closed for the day due to lack of staff was not unusual (and when they were open, the staff were often new and not very good).
This is exactly what I came in here to post, and it only gets WORSE the farther you get from tourist areas, and isn’t even confined to restaurants I’ve indicated my desire to purchase an item and had the clerk blankly stare at me and walk away. 
It is part of local culture and occurs across the board in customer service, for whatever reason customers are grateful for being treated like garbage.
H.