re: When to pay off the mortgage

I sleep 8+ hours a night no problem with most nights not waking up once. I have a mortgage. I put over 40k / year in retirement and another 15k or so in additional investments. I don’t put a penny extra towards my mortgage. Both of our vehicles are paid for one is 10 years old and the other 6 years old. I don’t understand the concept of having a mortgage as stressful. I could pay it off within a year if I really wanted to but I’m keeping it for the next 25 years. I keep the money in investments to grow I don’t keep it locked up in house equity. My home value has no correlation to if I have a mortgage or not so why put extra money towards it when I can have my money compounding in the market.