I was on the way to Lanzarote a couple of years ago, when the pilot announced we were going to land at Lisbon due to a medical emergency.

I've never seen a plane go from 30,000 feet to the ground so quickly! A proper seatbelt stretching drop!

45 minutes later, passenger, accompanying pax and luggage offloaded, plane refuelled (required pilot to use his credit card as whichever airline it was didn't use Lisbon) we were on our way again.