Goal

Any goal is reacheable. Only question worth asking is "how many failures will it take to reach it?".
If you reach a goal in the first try, it could mean that either the goal was too easy or you were just lucky. Such goals are not of great value.
Any goal worth reaching must atleast have a few number of failed attempts.

In the same vein, if it takes too many failures to reach a goal, it could be that the goal is unrealistic. It does not mean its not reacheable though!.
But, it might take away a significant amount of your time and energy. Time and energy which you could have utilized elsewhere.

So, goal setting is important. It would be prudent to budget your energy and time between goals.