The question of normality creates strange paradoxes in the consulting room. Often it is relatively healthy people who feel defective. In psychotherapy, patients may perseverate over vague complaints, feeling off-balance and out of sync. The worriers may believe that they have too much or, more often, too little ambition, desire, confidence, spontaneity, or sociability. Their keen social awareness (a strength), when tinctured with obsessionality, causes them to fuss over glitches in the self. For them, a sense of abnormality precedes any diagnosis and may persist even when none is proffered.In contrast, seriously ill patients may have no such concern. Those who manifest frank paranoia will insist on their normality; anyone would be vigilant in the face of plots directed at them. Anorexics and alcoholics may profess certainty that they're fine; the degree of "denial" is something of a marker for severity of disorder.
I know how much Hacker News loves the Dunning-Kruger effect. I feel like it definitely poked its head out there.