It is a well known success principle that in order to achieve the most in life, you should surround yourself with good people. "Good " meaning people having those skills and qualities that your line of business prospers from.
What is not given enough attention though is the opposite. Surrounding yourself with "bad" people can be a disaster! "Bad" meaning people possessing those skills and qualities that retard your efforts to achieve certain goals.
I think the most important type of bad guy to avoid at all costs is the negative person. The one who is always complaining about life, work or anything else. Nothing is a bigger energy zapper than having to listen to someone bitch all the time.
Also be on the lookout for those who tell you you can't do this or that. Or that you are misguided. These usually are people who have no ambition beyond the next beer or football game. You don't need their chatter in your life.
So just remember that having the right people around you definitely affects your level of success. But equally true is that having the wrong people around you has the same affect.