Success is not the key to happiness. Happiness is the key to success. If you love is the key to success. If you love what you are doing, you will be successful.
The only person "The only person you should try to be better than is the person you were yesterday." you should try to be better than is the person you were yesterday.
The harder you work for something, the152. "The harder you work for something greater you'll feel when you achieve it. -, the greater you'll feel when you achieve it.