#105-1. Feeling grateful or appreciative of someone or something in your life actually attracts more of the things that you appreciate and value into your life.
#105-2. A big shot is just a small shot who keeps shooting... shooting... shooting...
#105-3. It is amazing what you can accomplish if you do not care who gets the credit.
-Harry S Truman
The first cannot be explained scientifically or rationally. Try it and see.
Often the people who give up too soon are the ones complaining about the world, fate, the boss, politics and bad luck. After someone succeeds it looks easy.
The third is true, but practical advice in today's world would be to acquire the skills and tactics to make sure credit is not always denied for your contribution! It is better to be clear what is more important, getting something to happen (regardless of who gets the credit) or being the visible influencer. The answer could change as we progress through stages of maturity.