The Journal of Experimental Social Psychology has released a new study: "Reversing downward performance spirals."
The study intended to look at the inevitable downward performance spiral which follows an initial failure; they found that this down-the-drain spiral is reversible.
Criticism by someone you don't trust, or, even better, a rival, can help you perform better. You should try to prove them wrong and excel. On the flip side, positive feedback from a rival does nothing to help you.
It also won't help to have your teammates yell at you from the sidelines. In fact, the study found that when it comes to people we like, or even love, the reverse is true: Criticism by teammates worsens performances and encouragement from teammates helps.
In summary, we need our rivals; we need people to compete with, to get us moving faster and doing more. It can be, in the language of idioms, fuel for our fire.
We want to prove those outside of our group wrong, and prove those close to us right. The next time you enter a race, reach out for positive feedback from loved ones and see if you can't work up some extra jeering from your rivals.