Baby, It's NOT Cold Outside

The Season: Winter
The Temperature: 36 degrees
The Coat: Hanging on Dining Room Chair

WHY WHY WHY WHY does 13-year-old Jason REFUSE to wear his coat?!?! Whhhhyyyyy??
Why is it cool to walk around with blue lips and a permanent shiver while declaring "I'm NOT cold."

And, why is it that although it is NOT cold at 36 degrees (and no coat), it IS cold when it is 47 degrees and he is told to go outside and clean up the leaves?

These are the issues that perplex all mankind (and parents of teenagers).