Wind blew the arrow...

Forgot the air is thinner at this altitude and didn't compensate for lack of drag.

Mountain biker got in the way.

I had gas.
Elk had gas.

Forgot to turn the coffee pot off at the wrong moment.

Freak lightning bolt scared me.

I set the alarm for 4----------PM

String hit my jacket pocket.

My bow has a faulty release apparatus (me).

Every time my arrow misses, it's because of the big jerk on the bowstring.

My son moved and scared the deer.
My son stepped on a stick and scared the deer.
My son made a noise and scared the deer and scared me.

Pilot error

Someone back in camp said my name just as I drew.  Every deer and elk in the valley heard my name and headed over the divide into the next management unit!

My cell phone rang while at full draw. (this actually happened and resulted in ringer being turned to the "off" mode while hunting)

I did not miss, I meant to just scare that one away!

this happened to me this year. 7 pt. was 10 yds away and did'nt kown anything was wrong. had perfect wind. he turned to look away, and when I drew the arrow back my elbow touched the tree that my ladder stand is in and the arrow was on its way. 16"low. Never got to anchor!