Newmark's Door

Even drug dealers know about opportunity cost:

It kind of goes back to that old adage “time is money” and that was a hard lesson for me to learn because when I used to sell from my house, I’d have people come over and I would be a generous person and offer to smoke weed with them out of my own supply or maybe they’d want to load a bowl out of what they just bought. And so they’d end up staying for an hour. And while it was fun, it tied up an hour of my time that I could have been doing any number of other things.

So, learning that the quicker the you make a transaction, the more money you’re making was a valuable lesson for me. And ever since then, learning that lesson, learning that one lesson, I’ve been able to make a lot more money considering the time I’m spending.