A phenomenon where a person's facebook pictures overestimate the appearance of said person by using only decent photos leading to crushing disappointment when meeting said person in real life.

More prevalent amongst the female population
"Did you see Becky's friend Jasmine?"
"Oh yeah, I looked up her facebook, she's pretty hot!"
"Oh no dude, you should see her in real life, she's got a real case of haleyosis."
by Anonymous at Warwick February 11, 2015
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