Spicy Korean pork sandwich from the deli down the street from my office. I gave this place a second chance after their fresh roasted turkey sandwich laid me up for a day about a year prior.
I knew something was off several hours after eating, as I still felt full and kept burping up my sandwich.
The next morning, I caught a flight SFO-YVR, and figured a few bloody marys and UA's omlette would set things straight. All went to hell about an hour into my connecting YVR-HKG flight. I spent 10+ hours on all fours in the loo or barfing into a plastic trash bag at my seat. I meekly apologized to my cabin mates as others were retching from the sound and odor. I was met at the gate with a wheelchair - cancelled my onward HKG-SIN flight, and spent the next 2 hours hooked up to an IV at the airport clinic for dehydration.