Most humans don't judge others based on their actual abilities, they judge them (accept them or reject them) on how they FEEL when that person is around. If John Mayer showed up for a cover band audition, and no one knew who he was, there is an excellent chance he would be rejected because his skill and easy manner made the other members of the band feel intimidated and/or jealous~ "out-shined". If they thought it through, they would realize that having a band member who is that skilled would be a GOOD thing for their band, but the emotional reaction toward another person usually dictates behavior, not thought process.
If Jennifer Hudson applied for a job at the mall, anonymously, unless her past references from employment were very, very steady; (and often artists' work history looks less than steady on paper because they need to make work adjustments due to the difficult scheduling of gigs and shows), she would only be hired if the person hiring her LIKED HER personally, and did NOT feel threatened by her looks.
If Cindy Lauper walked into a bank to get a loan, if no one knew who she was and she didn't disclose her information, the likelihood of a flat denial, along with a lot of condescension, would be very high. If she dyed her hair brown, tied it into a tight knot, wore wire framed glasses, a business suit and black heels, with certain jewelry, and still didn't disclose her information, the odds would be a bit more in her favor.
If she wanted to hang out in the local crowd and just be "one of the crowd", she could not do it; she would be the target of ridicule, envy, competition, and gossip by at least one clique, no matter what she did. (That same clique would probably be the ones who would act like her best friends if they found out who she was; people who live in cliques operate on 99% emotion, mostly fear and security seeking.)
If Albert Einstein showed up at a neighborhood picnic, most people there would judge him as "the crazy old guy". They wouldn't say he was a genius unless someone told them he was; and then they would probably wait for him to "prove it". No one would treat him with any more respect than they would treat any other "crazy old guy". If he showed up as his younger self, he would be that "weird guy".
If Marie Curie joined in on a conversation at the same picnic about random subjects, no one would take her opinion seriously, they would dismiss most of what she said as idle chatter. If she tried to join in on a conversation about car engines or anything of a scientific nature that the men were having, she would be challenged, opposed, or dismissed by most of them. If she tried to join the women, but could not make small talk about their common interests, they would turn a cold shoulder on her.
When Jim Jones showed up at a gathering, several people were very taken with him, judged him to be beyond brilliant and wonderful, and hung on his every word, seeking his approval, following his every whim. Same with Charles Manson, David Koresh, Joseph Kony, Adolf Hitler, and Bonnie Nettles, to name a few.
Most judgments about other people are so far off the mark they might as well be on Mars. That's a big reason why judging others is "wrong"; people who believe their own judgments about others without question or exploration frequently treat them as if they are someone much different than they really are.