Beyond Mountains There Are Mountains
There are many lies we tell ourselves - and worse, believe.
Lately, I've been having a hard time remembering that happiness and fulfillment can only happen in the present. This notion that 'once I get through this obstacle (whatever it may be)', or 'once I achieve this', then I will be content and satisfied. The reality is, you will never be there.
If you've ever had the great fortune of achieving a long sought after goal, a true pinnacle that you wished for and worked for with every fibre of your being, you can probably relate to one of life's sad realities: success, no matter how grand is not everlasting - in fact, it's incredibly fleeting.
However, this needn't be sad at all! The key is understanding happiness and fulfillment lie not in attainment - but in the striving and struggling of a worthwhile goal and purpose!
Vince Lombardi did have it correct, so long as we remain present along the path, and understand that our achievement won't act as an immortal shield to future hardship and despair.
This way, when the inevitable feeling of "Okay, what next?" hits you after you accomplishment, won't bring along with it melancholy. On the contrary, it will bring excitement at the prospect of finding joy in the next bouts of adversity and conquest.

Recently, I read Brad Stulberg's book: The Way of Excellence, and he hit the nail on the head: "There is no greater trap than thinking the accomplishment of some goal will change your inner life. What will change your inner life is the person who you become in the process of going for it."
Of course, perhaps no one put it better than Tolkien:

"Beyond mountains, there are mountains", is an old Haitain proverb that has helped me often over the years, and one I'm trying to lean on more lately in order to do a better job of being present. If you struggle with this at times, I hope it helps you as well.