There's something very interesting about the quote above. Time and time again we put our heroes up on a pedestal as if they could do no wrong. But in a couple of words Fitzgerald completely breaks down that idea. He reminds us that the heroes in our myths, our fiction, and our movies are all more complex than they first seem.
Personally, I like it because I apply it to my own life (like I do with most things), it's a constant reminder that there's another side to everyone I meet. It could be a tragic side, the way Fitzgerald would say it, or it could be a happier side. It's a good way to remember that people aren't always what they seem, good or bad.
It helps me when I meet new people and reminds me to take more time in getting to know someone before I pass judgment on them. Hopefully it does the same for you, too.