Obstacle stand as an hindrance, or better put a stumbling block to Living. Maybe living your dream or being successful in your goals, either ways the obstacle would hinder you from getting to where you want to be.
It is alright to have an obstacle that you can see, at least you would be able to avoid it. But an obstacle you cannot see, maybe because it is hidden or you overlook them. This kind of obstacle can be dangerous, you can easily fall in and lose everything.
You should take note of the obstacles around you, they may prevent you from living your life or achieving your dreams.