It's happened to every pilot at some time or another-suddenly the airplane isn't doing what the pilot intends. Causes vary-his or her attention is diverted while hand flying, or spatial disorientation does its insidious thing or maybe its an upset due to turbulence. The deviation from the desired attitude can range from "Aw, nuts, I let the wing drop a bit," to "HOLY SMOKE! Which way is up?"
This is a companion discussion topic for the original entry at https://www.avweb.com/flight-safety/technique/hey-whys-the-horizon-over-there