At last but not at least: nº 10 ' Confidence '

Confidence
The greatest projects and schemes die for no grander reasons than that we don’t dare. Confidence isn’t arrogance, it’s based on a constant awareness of how short life is and how little we ultimately lose from risking everything. (Alain de Botton)

In other words:
One only regrets the things one hasn't done.
or
Don't always make the same mistake, then you miss all the others.
or
¡ Go for it !