After playing the piano for 30 years, I figured it out!

  Wow, tonight an amazing thing happened.I figured out my brain or
  my hands or my natural beats per minute. When I play the piano
  and compose music, it's in sort of a patterned way. I run on
  automatic and I'm never sure what's going to come out. But the
  speeds that I play at are always a mystery to me. I've tried
  with metronomes in the past to figure it out but I couldn't.
  Tonight, I did! My super-fast speed, when my right hand is going
  a mile a minute, the music comes out at exactly 100 BPM! I
  couldn't believe out exact that was. Then it got weirder. I shut
  off the metronome and played something else for a little while.
  I tapped with my foot to set the rhythm and then I turned on the
  metronome. Click click click it went. I moved it down down
  down... and then when my foot tapping and the metronome and my
  playing were matched up, it was... 80 BPM. So, 100 bpm, then 80
  bpm. Then I played a very slow, melonchaly piece. It ended up at
  60 bpm. Then a whimsical piece with an oomm-pah-pah style.
  Worked out to: 70 bpm! But 70bpm only was my natural speed in
  the waltz style and no other. Why such exact numbers? I don't
  know. I never expected that! It might explain why I always had
  trouble playing musical instruments with others and keeping
  their time. It seems as if I have my OWN rigid time that is hard
  to break! The weird things you learn about yourself! Kenneth
  Udut, age 36, Naples, FL USA