In all honesty, insanity. Couldn't handle the pressure and the guilt trips that chased me everywhere I moved and then drifted into a sexual relationship with a friend off the back of a break down, and then just walked away.
Later examined my belief system and the TRUTH(?) and found that I could not bare many of the teachings... blood, prophecy, Christian unity (so-called), having to log hours and do ritualistic ministry, etc
Pretty much the same as most of you here I would expect.