Is it better to set a challenging goal or a goal that is easy to achieve?(TOEFL essay)

Wandering in the gallery of the human's history, what we can observe is the dream of Einstein to convert the concept of Classical Mechanism (into what?), the challenge from the Charles Darwin against the existence of God (be careful - it's agreed that Darwin was not an atheist) and also, the wish of Ahkwari to finish his marathon with a badly injured leg. From my perspective, only from the setting of a goal that is full of hardship and adversity would create a strengthened soul, cleared vision and luminous(??) success. The following reasons will hereupon stand for my opinion on this topic. (This sentence is inappropriately formal - you sound as if you were in court.)

First of all, a higher goal is a tool to help us to achieve more. It is a challenging dream which motivates us to climb to the peak of what was hard for us to imagine before. The existence of this goal is the impulse, that is to say, the call from within. Were we not to dare to set that goal, we could never fulfill ourselves, and also dampening the expectations of others.

Aside from the motivation of a more significant success, the enjoyment of life can also be experienced from that process. "We are born for the success! Make a big dream for yourself." The words of a famous motivational speaker (who?) show us the pivotal position of a challenging goal on our lifelong road. For centuries, countless pioneers have made their commitment to a difficult dream, absorbing the nutrition and courage from the process of pursuit. So why not set yours?

I must admit that some people could get the touch of enjoyment from the leisure and rest. They don't want to be involved in the world of desire, thus refusing to pursue a higher goal. However, most can't experience the exhilaration, which can be easily got from the experience of the fulfilling of a goal, from a slow pace of life.

Due to the forementioned reasons, I believe that the set of a challenging goal is the only path leading you to the palace of feats and success.

Really well done! You have a good writing style.

I changed some parts to read more smoothly, as well as fixing the rare grammar or spelling error. The only thing I can advise is to revise articles (a/the), and think twice about some words you use - in a couple of cases, some of the choices indicated that you didn't properly understand the meaning of the word you used.

Don't worry too much - you would do well in the test even with this attempt. :)