I bought a boat on credit. It was the dumbest financial thing I could ever do. It was the best thing spiritually/emotionally I ever did. All of those weekends/vacations boat camping with my kids when they were young. All those times going out after work. So many experiences I would not have gotten to enjoy if I waited until I was 60 to buy in a smart way.

There is such a thing as opportunity cost. Putting dinner on a credit card is dumb. Putting a dinner on credit that ends up being a first date creating a memory and connection with your future spouse is life making. Or dinner with grandparents and kids that might not be around long.

You have completely ignored opportunity cost in your factoring. And it is probably the most important 'human' factor and is just as tied to your 'time' argument. We have 60 some rotations around a star, and stages in life during that time. That needs to go into your 'optimization' as well.