Don't discount the "how much do I hate being in debt" psychology....if carrying a mortgage is going to bother you, even though you know it may not be the mathematically "correct" answer to maximize net worth in 5 years - then think about paying it down earlier.
Or, if you can't decide, why not split the difference? Make some extra mortgage payments and also make some extra taxable investments?
While I can appreciate the balanced approach suggestion... Let me assure that having more money than you ever dreamed possible far surpasses the psychology you cite. It would suck more to have no mortgage, yet still have to worry about how to pay for a new roof/HVAC/water heater/car/groceries/anything, especially in your old age.
This morning as I was out walking, it occurred to me that if our lovely million dollar house somehow vanished while we were out, we'd be perfectly fine if we had to start over. I was momentarily filled with the craziest sense of elation. That's mind blowing!
I used to have a very powerful Inner Bag Lady who was so much like
@lhamo's they might have been twins. I'm happy to report that my IBL hasn't been heard from in years.
If you want to "kill the mortgage", do it this way. Put all the extra payments into a low-cost index fund a la jlcollinsnh. The magic of compound interest will make your money grow even faster. Then, when you have enough in your investment account, you can pay that mortgege off in one fell swoop. Most likely by then you won't want to do it, because you'll understand how much better it feels to have so much money working so you don't have to. Along the way, don't leave money on the table by failing to get your employer's full match if you're lucky enough to have one.
Your future self is going to be so, so happy!!!!