When you allow for negativity to be a staple of your life, and when you allow for negative people to obstruct your positive thinking, terrifying things can happen. Sometimes negative people are people that are in your life that only see life one way, and when they see your life isn't going in the direction that theirs is, they tell you your wrong.
Negative people will challenge you to compete and to live a life that you don't even feel like is yours, and then they will ostracize you when you realize and start acting out on the fact that you aren't even really happy.
There are many toxic people and things that can easily influence us to live a life we don't want to live if we let it, but we have to refuse to let these people get to a spot in which they could even be an influence to us.