Planning can be sometimes be a seductive thing, because once we have incremental steps to take it can seem very easy to achieve our goals. While outlining steps on the road to your goal is definitely a good tactic, leaving a little room for the uncertainty that comes with everything in life is also important.
Idea and productivity blog The 99 Percent asserts that we never really know what's going to happen and so we hurt our plan's effectiveness by being closed off to the unknown:
Projects fail all the time because we unwittingly bake the end solution into our initial objective. Rather than enduring an uncomfortable (but highly necessary) period of ambiguity, we fall into the trap of limiting our creativity by setting a project goal that is too narrowly defined from the start.
Interestingly enough, this isn't too far off from the differences between lucky and unlucky people, as keeping an open mind to things outside of your goal tends to make people feel luckier.
So how do you avoid strict planning when you do, in fact, want to have a plan in place? The 99 Percent suggests using objectives that guide you rather than define things very specifically. The goal is to be comfortable exploring new things if they feel right, rather than sticking on the straight path just because it's what you initially decided to do. Often you'll learn through doing, so embracing uncertainty can make for a significantly better final product.
The Power of Uncertainty [The 99 Percent]