"Being nice is free", "ermmm so is being an ass!!1!", yeah but you get the most in return by being nice typically. By building up positive relations with those around you you cement yourself in a place where you are more appreciated, and they will be more likely to help you in turn. You may get the momentary satisfaction from being a dick all the time, but dont come crying when people just don't like you lmao. Anyways there should always be a middle ground. People who are mindlessly optimistic and nice can be super incresibly obnoxious, while the opposite is true. You should strike a balance and use each in turn