Ive had a few and all bar one have been Belfast City to Belfast international.
The latest was last November coming back from a weekend in Vegas. I had been on a diet of gin and one hour sleep a night and found it hard to sleep on the flight home. Connected in heathrow and all was fine bar some very bad storms ahead. Got on the flight to Belfast and passed out before the doors had closed. Woke up in Belfast International and had not grasped the fact we had landed in a different airport than expected. Was carry on baggage and headed out of the terminal on auto pilot to where I normally parked my car. No car there, panic head back to the terminal which is 50 meters or so from the short stay, speak to the airport police to report stolen car. Go through details. Eventually click im in a different airport after 5 minutes of explaining. Run away to the extortionate airport racketeer taxi service and pick up said car in BHD.
In my defense I fly out of BFS weekly and have a fairly dialed in routine.