When you find yourself before a scary and unknown situation, and when you're deeply worried, you start looking for signs and patterns, which at another time could seem far-fetched, but right then they seem vividly real and impossible to dismiss as coincidence.
Not quite the same thing, but I've had three bouts of illness that closely followed eating scallops. I've always been very reluctant to eat scallops since then, as three times SEEMS too much for my lizard brain to pass off as coincidence.
However I have had scallops several times recently (not by choice, on fixed menus), and I was fine. Yet I still can't shake the suspicion.