I believe one of, if not the most common cause of aviation accidents (at least, according to my ATPL(H) notes) is CFIT, or controlled flight into terrain.
Common and received wisdom seems to indicate that many accidents result from press-on-itis, or (to look at it in another way) flying in conditions that exceed your skill levels and/or the limitations of your aircraft.
The least experienced press on, while the more experienced turn back to join the most experienced, who didn't set off in the first place.