Chicago O'Hare is a cursed airport.
We board the plane.
Half an hour later we're still not moving.
Finally, the captain: "Errr... We have a problem with the computer. We need to fix it. I'll keep you updated in 20mn."
20mn later.
The captain, clearly very embarrassed: "Errr... Soooo... Actually while looking at the computer they found some bolts falling off the tail of the plane.
You'll have to deplane while they fix this too or find another plane."