+1 to what RickAir said didn't read his post first.
You can just search for the latest Nall report if you are interested in why GA pilots crash. It basically depends how you classify things. The number one cause of incidents is mishaps when landing. Pretty consistently the number one cause of fatality is variants of disorientation and VFR into IMC and CFIT, then number 2 is maneuvering flight like that video link I provided awhile ago.