Success or Failure - Possible outcomes of taking a risk

"Risk is the probability of an irreversible negative outcome"
 - Tim Ferris

There will always be risk, and there will always be the time when we as human beings must make a decision - Do we accept the risk and the probability of failure or success, or do we do nothing and hope for things to change? I believe that all risk must be calculated and well thought through, especially when our actions may have an impact on other people.