"the clothes make the man, " this expression is used for people who judge other people on how they're dressed.

I don't think this is a good expression to judge someone because lets say your a really nice person who went to the store for lets say some food. You would just go in your track pants and sweater, not in like some awesome dress that you would wear to like prom or something, but just your usual, a sweater and track pants, then someone comes along and looks at you and they whisper to their friend beside them and say, "hey, look at that person. They look like a slob, they must have been through a lot. " that's not describing someone at all. that's just what someone says, just by looking at them.well, those are only some of the reasons this expression is not a very good one.