This was due to the usual carelessness, an arm extending into unknown regions, and the finger pointing towards the coffee machine ready to flip the button on.
Not seeing the glint of metal and the edge standing upright like an eel ready to attack, the knife placed a fairly deep slice in my forefinger without the slightest effort.
It was a nice clean curvature which at first didn't hurt at all, and it was caused not directly by that razor-sharp edge, but by the momentum of my hand reaching further before the automatic reflex realized what had happened.
Curiously enough, the bleeding didn't start right away, but took some time to start flowing. The finger tried at first to pretend that nothing had happened, when in fact it had.
This was some kind of instinctive, protective, innate action required to help us survive.