Cold Coffee

Today I gave Barb a cold cup of coffee.  We often make more coffee than we drink and then leave it for later. Then we heat a cup up in the microwave.  I poured a cup for Barb and then put it in the microwave but forgot to turn on the microwave.  Later I remembered I put the coffee in the microwave and I took it out but never checked to see that it was hot.  Like why would I need to check.  It is always hot when I take it out of the microwave.