Yep, we used to get those comments allll the time, about how well-behaved and polite and adorable our girls were. (They're still well-behaved, polite, and adorable, but as they are now in their early teens, it's not something to remark upon anymore.) Honestly, I think it's partly that people like polite, well-behaved, and adorable children; partly that there certainly are miserable screaming brats about fairly often; and the myth of the miserable screaming brat is so ubiquitous that when people see any child walk into a restaurant their hearts sink, so they really notice it when said child is not one of those, and want to express their appreciation. I remember the apprehensive looks we got when we boarded an international flight with our four-year-old and eleven-month-old. I smiled at everyone and promised them they'd be quiet and good, which they were; the only thing we did that made any noise on the flight was quietly singing "Old MacDonald" during take-off to distract them. Baby latched on and slept almost the entire flight, and Older watched Angelina Ballerina on the in-flight TV and slept, too. We got several relieved thank-yous when we landed. It made me a little sad, actually, because by the time kids are that age the assumption should be that their parents have them under control, but that's just not the case anymore now that so many people farm their kids out to be group-raised by strangers, and don't care enough or are so obsessed with their kids "liking" them that they don't discipline them when they're home.