Count the coincidences

This can't be happening. It just can't.
Count the fingers on one hand, see if you're dreaming.
One.
Two.
Three.
Four.
Thumb.
Four fingers and a thumb. The thumb's not a finger because it's opposable.
One of these things is not like the others.
One of these things just doesn't belong.
Did I see that? Is the lack of sleep finally getting to me?