Thomas Edison was a very hardworking and enthusiastic man. He had done several -approximately 2000-experiments before he made the great invention and everything had failed . His co-worker got very offended blaming Edison for his continued dedication on this.
One day he had an argument with Edison. "I am tired of working with you. If we find something good and useful, then it would be interesting to continue this". He said to Edison. Edison replied him quietly. "Yes each time when we fail, we know that particular element is not useful to make electric bulb". Then he continued to work.
Next time he found a great element, and it turned out as the greatest invention we have ever had. His new bulb was lighted for 200 hours continuously. If he had dropped his work any time in between we would not have had electric bulbs.
Great people never quit, even though they face lot of failures or challenges in life, and they become the best of all. Abraham Lincoln failed eight times in elections. Finally he became one of the best presidents of America. If you continue to work harder and harder we can achieve lot of things. There is a proverb saying "if you aim for the stars, you will reach moon". Maintain hope and strive hard,you will reach your goal.