You can't know where you're going without having a great vision. But consider this: your goals can limit you.
Too many times I've heard people say, "My goal is to bench 300 pounds." Then when they do it they realize they could've done so much more.
That's why Louie Simmons always taught me to break my PR by five pounds on my second attempt (in a powerlifting meet you get three attempts), and go for broke on my third.
When dieting for fat loss, I set a timetable based on a number of weeks. If I reach my desired percent body fat early, I keep going. If I didn't reach it in time, I shut it down for another cycle.
Also, when setting goals only let a select few know the specifics. If your goal is to bench 400 pounds, keep that as a marker in your mind. If others ask, just tell them, "I'm training for a bigger bench," or "I'm working toward a new PR."
The reason for this is simple: 90% of everyone you meet are negative pricks who will go out of their way to tell you why you can't do something.
Once they know your goal, they'll try and tear you down. Just keep it vague, and all they can do is wish you success.
Of course, they may still try and tear you down once you've actually accomplished your goal, but who cares? You've done the work and have the results to show for it.
Sure, there's value in telling those who will hold you accountable, but for safe measures, only share your specific goal with the few who know you can do it. Take a good look at the people around you, and consider yourself lucky if you know people like this.
Don't worry if you don't. Because all you really need is one: you.