People who won't try new things, because they'll suck at it.
People who don't Google (they know how, they just don't) because they think all answers all received wisdom, not something between a SWAG, an opinion, and a mental model.
People who don't read things outside their domain because that's someone else's job.
People who confuse having 1 experience for 7 years with 7 years experience.
People who think you have to be an expert scientist, engineer, architect, philosopher, and mechanic to change a light bulb, so they never even tried.
People so worried about imposter syndrome they'll never deliberately exert any curiosity for fear it will be seen as ignorance.