Despite what most people say, one can accurately assess and judge a person’s character within a few brief moments of interaction. The ability to do so is innate and a useful tool for survival, a necessary evolutionary trait. The only people who will disagree are more politically correct (PC) than is good for them.
In our more primitive times, it helped us determine which people from other tribes were safe to interact with. Now, it helps us determine who is worth our time. It also lends a hand in deciding who is most likely to take all of our possessions while we sleep.
Perhaps you cannot judge a book by its front cover, but you can after a quick look at its back.