This is a topic that arises all the time. One's attitudes is directly connected to ones success. We may think we are being positive and put on our best smile. I have found humans ability to see beneath the surface is extraordinary. As a matter of fact it is amazing that we don't always realize that we have that ability.
When we are speaking to others we emit signs of our feelings. A major way to have that positive attitude is to think positive. Talk with others and work towards positiveness. We all have negative events occurring in our lives. The game here is to look for the positive and and be thankful for what we DO have. Remember the old cliche of the half full glass of water.