It is true that optimists, or positive thinkers, are at an advantage in life compared to pessimists. This is because of the effect your mindset and attitude have on everything we come across. Our social relationships, our job and also our health are an integral part of our daily life and we can feel how negative and positive thoughts can have a domino effect on everything we do during the day.
The way we choose to think, positive or negative, has a great impact on the final outcome and is mirrored in everything we do. Hence the importance of having a balanced outlook on life.