I am always doing that which I cannot do, in order that I may learn how to do it. --- Pablo Picasso
I am a father. That means I am a failure coach, teaching mostly by example.
Way back before my kids knew I was an idiot, I invested a great deal of time and energy maintaining an aura of infallibility. Now that they've had a peek behind the curtain, I find myself with hours a day to stumble openly over shortcomings or rummage the rubble of this or that newly collapsed folly. It is good not to play God. My kids and I learn more this way.
The dearest wisdom is often won through the deepest foolishness. Having encouraged my children to live at the edge of their abilities, I fully expect them to routinely fail. I try not to be embarrassed or overcompensate when they do. Still, I am a dad, and I hurt when they hurt. It is so hard to separate their suffering from mine.
It is good to focus on successes and speak of "areas for development" rather than "things you look really stupid futilely trying to accomplish." A positive attitude really does go a long way. But failure is a necessary part of life. It does a child no good to say how well her cleats stayed tied when she scored the own-goal that lost the game. Get down there in the emotional muck and mire with her and affirm that harsh self-appraisal. Help your children get used to dealing with failure and soon they will no longer fear it. Only then will they be equipped to go out and challenge the world.