I have done a lot
  USMC
  MP
  SWAT
  Martial Arts
  MMA
  Sky dive
  Bungee jump
  Scuba
  Marathon
  you name it
  I have never thought of any of these as hard though   just saw them as things I had to do
  I will say this though... starving to get super shredded does suck and is very hard   so to me, people who compete in BB have it super tough   I would do the bb thing, but I do not like the thought of being in a g string with a bunch of horny males judging me