Surprisingly the quick analysis of adult humans of other humans is very accurate, but not always correct, of course. The reason of the accuracy is because people is used (daily trained) to see and compare a lot of people. Also, most people are shallow and show externally what they are internally. Also also, people don't change much when they are adults.
Let's do it quick: https://youtube.com/watch?v=wyS_Kg5MvXI [Embed]