Social desirability is a big one, thanks, I didn’t think of that.
A related issue is that every representation we see of reality—every newspaper, blog, TV show, movie—is created by a writer or artist, definitionally. So when we look at representations of the world, we’re looking at the biased viewpoint of the highly verbal and well-educated. And, of course, these are not all the people. If you live in a highly symbolic/representational world, you may be very mistaken about how things work, not only because of a particular bias in your bubble of representations, but because of a systematic bias in all representations.
(I think Tolstoy is an unusually valuable resource because he writes about the inner lives of the kind of people who would never, ever write or talk about their inner lives.)
Social desirability bias is a part of this—it biases what we believe towards what people are willing to talk about—but I think the entire phenomenon is worth thinking about.