We learn something on every dive, and sometimes we make mistakes, too. By diving within your limits, you can save your life or someone else's. This means ascending with 1/3 of your gas remaining, to be used for emergencies only. It also means staying within your acceptable depth and activity limits and risk tolerance. If you are not trained for overhead environments, do not enter. This will help you to come back later. Even when diving within limits, accidents can happen. This is why we carry DAN insurance. Don't dive without it.