Let's say I have a vague dream of becoming a sailor. Consider these four scenarios:
- Scenario A: I make it an explicit goal. In year 1, I read some books, take a sailing class, and forgo some luxuries to start saving up for a boat. In year 2, I buy a boat and sail. Dream attained!
- Scenario B: I make no goal. In the absence of a concrete goal, I don't read or save in year 1. In year 2, I still long to sail but am no closer to getting there. Eventually I run out the clock on my life.
- Scenario C: I make it an explicit goal. In year 1, I read some books, take a sailing class, and forgo some luxuries to start saving up for a boat. In year 2, I decide I am no longer interested in sailing. I remove that long-term goal, and spend the money I saved on something else.
- Scenario D: I make no goal. In the absence of a concrete goal, I don't read or save in year 1. In year 2, I lose interest in sailing. Nothing gained, nothing lost.
The two failure modes are B and C. If you fail to pursue a long-term goal that doesn't change (B), you are eternally unfulfilled. If you pursue a dream that changes before you reach it (C), you have some lost opportunity cost for the work you put into that dream that is now not relevant.
For most people, the latter is a much smaller harm than the former. It's more rewarding to strive towards something meaningful even if it ends up not panning out than to abandon your dreams pre-emptively.
Of course, the ideal is A or D, but none of us have a time machine to determine who our future selves will become. So the only choice you can make today is A/C or B/D.