A covered pot doesn't boil

We often cooked together. One night Luz had gotten started before I got home. I came into the kitchen and we did our fairly normal welcome. I looked at the stove and I said, "You know, right, that the water will boil faster if you put a lid on the pot?" Her response was, "HA! Right." And, she left it uncovered. I wonder if she still believes in the opposite of simple thermodynamics. She certainly would not cover any pots before or after I mentioned what is plainly obvious to most people. In the end, I was an idiot in her eyes and she just laughed at my suggestion.