If you are saying saying what you are saying out of experience, then I must say you have an amazing power of observation. If you have studied human behavior, then you are indeed well-read. If you say this just like that, then you have decidedly an exceptional intuition.

It is true. Most often our impression of other people are based on their appearances. It is a huge tragedy of human behavior that we are incapable of seeing beyond what is obvious. We just take things as they appear to us.

The second part that we see our own shortcomings, in an exaggerated and somewhat distorted fashion, in others is also true. It is true that when we have a problem, we assume that others must have similar problems too. However, this behavior is very complex and needs a detailed discussion (something pretty much beyond the scope of this discussion).