I'll give a specific example. It's 2016. I've just eaten out at a restaurant near the ocean. Within an hour or two, most of my body has turned bright pink, like sunburn, and I soon develop terrible diarrhea to go with it, along with intense digestive system pain. Come morning, all symptoms have vanished and I feel fine.

It wasn't that hard to find out what caused this.

But about a year later, we had a couple of med students staying with us, and before I even got to the end of the symptoms, they asked me specifically if I had eaten one very particular kind of fish (which is actually illegal in many nations and even some US states). They didn't even bat an eyelid, and they were of course 100% correct.

Yes, I can "do my own research", but fitting that into an overall view of drug and physiology interactions is something quite different, as is simply knowing stuff that for other people is complete arcane knowledge.