This is something I believe 100%. I think good or bad energy is transmitted from people to people. If we think positive and have a positive attitude we transmit this to whoever is around us. Same with the bad energy.
Positive thinking is healthier for us too, makes us less angry is more happy. Makes see things and situations in life brighter.
Positivity in life makes us work harder to achieve our goals, makes us seeing the good on people and things. Being optimistic when we fail makes us want to try again and not to give up.
At least in my own experiences it has worked and it keep continuing working. Many fails have turned into success just with an smile and a positive attitude. As a mom I have been through many challenges that being positive had helped me.
Life goes on so let move forward with a positive drive and spread it all around each other, Smile more.