It’s useless to bet against someone because there is no upside.

It’s often done out of jealousy.

• When I was studying radio and television in college, I thought no one without a big voice could make it in media. I was wrong. At that moment in time big voices were in but later unique voices were also in demand.
• We wouldn’t place a bet on losing — or wait, it’s done in the stock market all the time. But with people you lose the moment you downplay another person’s chances.

The alternative:  believe in everyone’s ability to succeed and at the least you get satisfaction and at the best you make a connection that might be useful for the future.