>>63973081
You've got a plastic cup in your left hand and a metal cup in the right. Boiling water is poured into each cup. Which hand feels hotter?

The same heat is in both cups. It just leaks more slowly from the plastic cup, so that cup feels cooler. Both hands will ultimately absorb and dissipate the same amount of heat, but the reduced convection of the plastic cup gives your hand more time to dump that heat without being damaged.