To be candid, some people have given positive thinking a bad name. I can't stand to hear some gung-ho individual say that with positive thinking you can just do 'anything.' If you think about that one for a moment, you recognize the absurdity of it.
I wouldn't say 'most' people are prone to negativity. I think it's probably that most people allow negativity to color their thinking, depending on circumstances, but I also believe most people make the necessary efforts to return to positive thinking as quickly as possible.
When you choose to be pleasant and positive in the way you treat others, you have also chosen, in most cases, how you are going to be treated by others.
The more you recognize and express gratitude for the things you have, the more you will have to express gratitude for.
Positive thinking will let you use the abilities, training and experience you have.