Well, it's a paradox.

If you are fixated on the goal, rather than being present performing the actions that will get you to the goal, you are actually less likely to reach the goal successfully. Thinking about the goal obsessively is counterproductive.

Maybe "detach from the outcome" is a better word. Anchor your happiness and well-being on performing the actions within your control that you believe will take you to that outcome, and do not make that happiness and well-being conditional on reaching that outcome.

Because you won't always achieve them. If you value the end result, it will be all the more disappointing if you fail to achieve it.