If you've never seen Risky Business, I highly recommend it.
And while Tom Cruise's Joel is the Hero in this tale, it's important to note that in the end, he lost everything he thought he'd gained to the Villain, Guido the Killer Pimp, played masterfully to a junkyard dog "t" by Joe Pantoliano. Joel was lucky to walk away with almost the status quo ante, sadder but oh so wiser.
Guido's words, above, and that ultimate lesson, thunders down through the ages from unlikely font of wisdom, then-rookie director/writer Paul Brickman.
That wisdom should never, ever be lightly disregarded.
For all kinds of reasons.