Okay, Mr. Free-and-Clear HomeOwner Smartypants. ;-)
A mortgage is something that young non-wealthy people need to get a roof over their head without being enslaved to rent inflation the rest of their lives. Got our first mortgage 6 years ago, a 15-year at 7.375% and it seemed a good deal at the time.
Refinanced to a 30-year a couple years later along with some other, erm, lifestyle adjustments, to free up cash flow so my wife could stay home with our new baby girl. We're still a one-income household, so going back to a 15-year amort isn't really do-able yet but 20 years is.