It is just too easy to set our sights on achievements that are easily do-able; as that way we are more likely to succeed.
All too often the fear of failure controls our ability to aim high.
Remember that if we do aim for the moon and miss, we still end up amongst the stars!
I have always loved that quote; it just makes sense!
Challenging but realistic! For me it takes away all the pressure of having to reach the moon first go.