Kathy Bates in Misery, as she ramps up the crazy I get chills every time

Robert Shaw and Roy Scheider in Jaws, Shaw with the 'Ahab captain' and Roy with the 'it's not paranoia if there's a real monster out there' sheriff.

Oliver Platt in lake placid, goofy and scared and the scene with him in the water is great

Theater of blood/house on haunted hill super campy Vincent Price, he did some radio shows too just hearing him do his creepy voice is always fun, but those two he's very over the top & melodramatic.