Feel I should nominate by better-half into this section.
She got her new bow last summer and had only shot with it a couple of times. We were in a league match and she was shooting a blinder, that is, until our club coach pointed out that her limbs were on upside down.
Yes folks, the top limb was on the bottom and vice-versa.
The irony of it is that her tiller was that far out that when the limbs were on wrong the tiller was roughly where it should be, as soon as she swapped them over her scores started to drop, there were a few

followed by some more

.
As for me, i've been at the shooting line for the first arrow of the day, been at full draw waiting for that clicker to do it's thing and then out of the corner of my eye i can see my whole forearm.

No blooming arm guard. You then have a choice, release and take the risk or come down and face the abuse from your fellow archers...rock and hard place springs to mind