Well, leverage is certainly something that financially intelligent people understand. You don't have to be super sophisticated, but I think it makes sense to take loans on things when interest rates are low on things where you can get a good interest rate -- like a house. But you still wanna pay it off because then if you're into it you can take out another, bigger loan.

Tax evasion is also a great thing. Certain investments are privileged, so as dumb as that may be you play along I guess.