I ate an oyster for the first time earlier this year. It was ****ing disgusting.
It actually made me feel physically nauseous after eating it and I barely touched the main course I'd ordered (fish pie), wasted a tonne of money on a meal I hardly ate.
Never again. They are not fit for human consumption.
I hasten to add it wasn't a raw oyster, it was grilled in the shell with cheese and bacon, and it was much like biting into a massive sloppy bogey. Possibly the vilest thing I've ever eaten.
I did have raw osyters once, in France. Seasoned with lemon juice and not much else. It was like eating slime, or maybe The Blob. No-one told me until I'd finished that they were still alive at the time. Still not quite the vilest thing I've eaten though, (that goes to Parsnip).

His reasoning for leaving the skin on was that it helps to retain the moisture in the fish. I've since eaten many times, both with skin on and off, and I fully admit that he's right, the fish is actually much nicer with the skin on, it is usually, other than the grease/oil effect, totally dry when it's been skinned.