One of the most embarrassing things that can happen to a pilot is the case where he starts his airplane’s engine, advances the throttle and goes nowhere – because he forgot to undo the tiedown at the tail.
It has happened to plenty of pilots, even those who have performed meticulous preflight inspections and yet for whatever reason neglected to see the bigger picture as they focused on every bolt, rivet and cable on their airplane.
The pilot of a Piper T-tail Lance once even tried to takeoff despite the fact that his airplane was missing its elevator. A mechanic had removed it for repairs, and during the preflight the pilot never looked up to see it was there. Thankfully, nothing was damaged during the attempted departure other than the pilot’s ego.
That’s an extreme case, but still, I always perform two walkarounds of any airplane I fly. The first is my normal preflight inspection per the operating handbook. The second is just a quick circle of the aircraft, where I actually look at the entire airplane and everything around it to be sure all the tiedowns have been removed, the chocks are out of the way, the fuel caps are on, no obstructions will block me in, and, yes, that the elevator, rudder, wings, and everything else important are there and undamaged.