I was on a plane about to leave for vancouver from minneapolis when the pilot announced as we were moving from the terminal to the runway that there was an issue with the planes pressurization system and that we would have to return to the terminal so they could take a look at it. I was sitting in the row at the wing in the window seat. When we got back to the terminal they did not allow us to leave the plane and a maintenance guy approched the plane with a ladder climbed up onto the wing and started fucking with the window i was sitting at, literally less than 2 feet from my head. The window was loose and i guess it was the cause of the pressure problem. The guy then proceeded to use what looked like a rivet gun to fix the window and reattach it to the plane. The pilot then told us the problem was solved and we would be takig off soon.
That was enough to scare me off flying for over 5 years after that untill i forced myself to learn how to skydive to overcome my fear of flying.
I hope to god in the last 15 years maintenance practices have improved and they would not allow something like that to happen today as it really really scrared me and the people sitting near me, im still in contact with the gentlemen that was sitting beside me we meet up every few months for coffe and to this day are still freinds. He has never flown again since and thinks im out of my mind for going skydiving lol.
EDIT to add, i was in a sheer state of panic/terror the whole flight untill i was on the ground in vancouver.