The thing many fail to understand is that money isn't just numbers. There are lots of behavioral aspects. Some helpful, others less so.

While I understand and accept that paying of your mortgage early was incredibly good for you, I prefer to keep it in place even though I could pay it off next week. That's because (a) I'm not troubled by having that (automated) monthly payment go from my bank to the lender, and (b) at 3% interest, in a 3%+ inflation environment, and with a nice tax deduction on the interest, I'm actually making money from that sucker.