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.
Zig ZiglarEvery time passionate people fail, they are convinced that they are simply one step closer to fulfilling their dream.
Zig ZiglarWhen you are truly interested in other people, you will learn what they are interested in and if they have a need for your product. If they like you, and most people like folks who take an interest in them, they'll help you find people who do need what you have to sell, even if they don't.
Zig Ziglar