I worked at an open-pit copper mine in New Mexico one summer, part of which included a pretty intense 3-day safety course. One of the best take-aways was their

I worked at an open-pit copper mine in New Mexico one summer, part of which included a pretty intense 3-day safety course. One of the best take-aways was their definition of four levels of competence: Unconscious Incompetence: you don't know what you don't know Conscious Incompetence: you begin to learn what you don't know Conscious Competence: you learn your task, but need to concentrate on it Unconscious Competence: you can perform your task without that level of concentration The obvious most dangerous one is unconscious incompetence, but the other dangerous one is conscious competence. As you learn your task, you may become overconfident at this point, which may lead to lose of concentration on the task if you know your task better than you do. Applies not only to working with heavy machinery at a mine, but server administration, coding, etc. Reference: http://en.wikipedia.org/wiki/Four_stages_of_competence http://en.wikipedia.org/wiki/Four_stages_of_competence