When my oldest was around 2 or 3 we were at Sea World and there was a little boy with yellow teeth in line with him. My son being friendly said I like your teeth they are a great color of yellow. Of course the boy who was older was embarrassed and kept his mouth closed for the remainder of the time he was in line. In the mind of a child he is only pointing out a difference and since he was little was taught to find differences. It is wild how our society is we are taught as young children certain lessons and then in contrast we aren't allowed to point it out/use it in our everyday life. It can be extremely confusing and difficult to instill certain lessons with so much inconsistency. Fortunately as they become older they understand why you only point out certain things. Just an observation I had.