While we would never wish it on our children, there is tons of evidence that we learn the most from our struggles, our failures and hardship. As I think back, the only teachers I remember were the really tough ones that challenged me to do better.
As parents it is natural to want to protect our children from pain and harm. As leaders, we naturally seek to make our employees successful. This behavior may appear to be kind but can also take away key learning opportunities.
In the right situations, I suggest that you should let your kids and/or employees fail. This includes times when we could jump in and "save the day" so to speak.
It may seems counter-intuitive but letting your kids/employees experience failure may be the key to ensuring their future success.
And besides - the only way to appreciate success is to have experienced failure.