The fridge point is worth explaining because it sounds like folklore and is not.
Cold makes potatoes convert starch into sugar. That sugar is why a refrigerated potato tastes faintly sweet, and it is also why it goes dark and bitter when you fry it, since the sugars brown far too fast. It is a real chemical change and it partly reverses if you bring them back to room temperature for a week.
For roasting or frying specifically, keep them out of the fridge. For boiling it matters much less.