If you find yourself waiting in a random line here, and you wish to blend in with the locals, do make a random comment on the situation (ie, the long wait or the slowness of the employees) while not specifically looking at the person next to you. At the local supermarket and bakery, this happens often. When a comment is said in my general direction, my responses vary. Sometimes I return with a small comment of my own (or at least a nod) while other times I basically ignore the person. Of course, there are times you actually converse but it happens less often.
In the States, I find random comments to happen less often. People generally talk on their cell phones or to other people they are in the line with (friends, family). More and more often, no one talks at all since they are looking down at their smartphone.