Do people in other countries complain all the time? I live in the U.S. and people just seem to whine and complain about just about everything almost.

The more luxuries people have the more they complain because when you are a spoilt brat the slightest inconvenience sets you off. Notice how many Karen's are in first world countries for instance.
I have been in retail as well before and def noticed it's the people that have everything complaining that not enough lanes are open or they have to pay a penny more for their snackie cakes or have to pay taxes. Or that other people that are disabled they get jealous of thinking they get free money and not realizing those with disabilities probably have a shit life in comparison to them.
Spoiled spoiled spoiled.