This scene made a big impression on me when I watched it as a college freshman. By not worrying about what was to come later, the underdog was able to pour everything into the current moment and prevail. I thought this was a great catch-all example for how to approach one's life, with some very obvious exceptions.
Based on a few recent conversations spurred by concerns over the economy and job security, I realize these exceptions may not be as obvious as I thought.
To be fair, I think the issue is somewhat masked by our ability to (through credit cards and overdraft protection, etc) to go into debt without immediately being aware of it. So, for the following set up, think CASH ONLY.---
Harry is hanging out with some friends in town. He knows that a cab ride home will cost $12. Harry has $20.
At some point during the evening, Harry takes a break from dancing with his buddies, sits down at the smoothie bar, and orders a $5 dollar cranberry/orange juice/protein powder shake. While he is enjoying it, a woman he flirted with on the dance floor approaches him and mentions that what he ordered "sounds delicious." Harry remembers that he has $15 left in his wallet. Can he afford to buy her a shake?
It's my guess that most adults would answer the above question with a "no" since, if Harry buys the cool girl a shake, he will be $2 short on a cab fare home. I think it's also fair to assume that at a cash only restaurant, most folks know to consider more than the price of food shown on the menu when determining what they can afford to order. (They take into account tax and tip.)
But despite this, there are many high-wage earners who, on top of necessities such as food and shelter, spend and spend and spend until there is nothing left of their net income to set aside for an emergency fund or retirement. In other words, they approach finances the way the hero of Gattaca approached overcoming his shortcomings. Any change of plans -- a failing economy or a job loss, for example -- and they are stranded miles away from shore.
My recommendation is to forget you ever saw the movie when it comes to finances. When pondering an expense and asking yourself "can I afford this?" remember the tax and tip, remember that something may come up to force a change of plans, and remember to leave enough left for your "cab fare home".