Life is like a river, or stream.
The destination, the lifelong goal, is the ocean.
If you think of the ocean as completeness, and happiness, the similarity is clear. The river is not straight. From the mountain tops to the sea it twists and turns, it bends and falls, it branches and unites. You see the river is always moving forward. If something obstructs its path it won't stop progressing just to mull over the disruption in schedule. It brushes it aside or, if too large to ignore, carves a new path to the same ocean end. Because the river knows there will never be a straight and easy path to the sea.
There will always be barriers in the way, and challenges to face. This doesn't stop the river because if it chooses not to flow out of fear of these things, it will never reach the ocean and become buried by debris.
When you chase your dreams be the river, because the water's flow an even cut through stone with its persistence.