Everyone should fear losing. But we should look it on a broad way evaluating the whole picture than a single instance. It's like winning the battle vs winning the war. Every of us takes small risks and guess work on day to day life. Living risk free is not possible. There could be some loses, temporary or permanent but if you are getting favorable result in long run, you are winning. The win doesn't necessarily be a monetary one. On the other hand even if you win daily gambling but lose your money or even your mental health in long run, you are losing.