Can someone score my essay... please?

I am taking the SAT tomorrow, and I have nobody around me to give a final feedback on my essay…
I have never ever got any feedback for my essay and I am seriously worried.
Therefore, can anybody help me on my final essay before the SAT?
I want you to score it, and tell me which part should I revise, and how, and what is wrong with my essay.
A strict and harsh criticism welcomed. Thank you very much!

Here it goes:

The essay prompt:
Too many people do not consider their task or project complete or acceptable until every detail has been done right. Fortunately, such people have not always had their way, since nothing would ever be completed if we has to check every detail before we could consider our work done. In fact, none of the world’s greatest accomplishments would have been made, because none of them is perfect in every detail.

Do people put too much importance on getting every detail right on a project or task?

ESSAY:

 One might think that everyone tends to put a great effort on getting all the detail right. However, that belief is not true. People do not put too much meticulous effort to get every detail right. This can be proven by the discovery of Penisiline and the invention of Macintosh by Steve Jobs.
 The discovery of Penisiline can stand as an epitome to explain that people do not put effort on getting every detail right. A scientist was researching about the cause of the proliferation of a bacteria. Unfortunately, he had caught a cold during the experiment. Because of the cold, he needed to cough or sneeze all the time when he was doing the research in his lab. One day, he accidentally coughed to the bacteria specimen. He knew that it was not right, but he just carried on the experiment. Eventually, he successfully discovered the cause of the proliferation of a bacteria and also discovered the Penisiline because of that. He did not put any effort to make every detail right on the experiment. He even made a mistake, but it did not become a fiasco. His discovery was not fastidiously done, there was a mistake; the experiment was successful. Thus, people do not tend to get all the detail right.
 It can be efficaciously proven that people do not try to make all the details right by the invention of Macintosh. Steve Jobs was inventng a new computer in 1980s. He put more weight on the interace than the design; therefore, he started to develop a new opertaing system. He put very much effort on developing the system. After a year, the system was developed and Jobs thought it was perfect. Nevertheless, he did not care about the external look of the computer. He just put a single woodblock and installed the xyxtem and sold it at the market. It got a gradual attention from the people, and eventually now it is one of the most highly-acclaimed computers. Jobs di dnot put a painstaking work to the development of Macintosh. His invention was not perfect. However, his computers are acclaimed by most of the people nowadays. If he was a fastidious person, then the development would have been hampered and it might have not earn the accolade as these days. All thigs considered, it is now proven that people do not put too much effort to make everything perfect.
 By the aforementioned examples of Peniciline and the Macintosh by Steve Jobs, there is no doubt that people do not put too much effort to make every detail right. If every peple try to make a perfect task, then the efficiency would decrease and all the discoveries or inventions would have been impeded. People can make a mistake; people are not that painstaking to put a lot of effort to make things perfect.