I love this quote from Sam Shankland, the 2018 U.S. Chess Champion who has been ranked as high as 24th in the world and is currently ranked 31st in the world:
I've always believed in lofty goals: my goal is to be the World Champion. Now--I think this is very unlikely to happen, and my odds for this are significantly lower than one percent. But I can guarantee you it will not happen if I don't try my best, if I don't throw myself at it with full force. Ultimately, I think that you should be setting lofty goals for yourself...what's that expression? "Shoot for the moon. Even if you miss, you'll land among the stars." If my goal was to make the top ten in the world, I would peak at number ten. But if my goal is to be world champion, and I peak at number five? Even though I technically fail the second goal, I think I will be much happier with myself and my career.
The full interview at Chess Life Online provides some chess-specific insights from Shankland, but the above quote has universal applicability. Life is too short and too precious to set "realistic" goals. Shoot for the moon, and do so with every mental, physical, and emotional fiber you can muster. You may not reach the moon, but you will soar past many people who lack your daring, courage, and vision!