I just had a fine realization.
I was balancing my bank statement, and realized that I am carrying approximately $12,000 more in my checking account than I really need each month. (Pretty stupid, I admit) So, I got out my ole calculator, and began figuring what that is worth to the banks, as far as loans, using their fractional reserve system. The results were staggering.
I, effectively, give them $12,000 of my money. For that, they pay me approximately $120 over a full year.