Yea, it's a bit funny to see somebody complain about headless chickens, and then go straight into dancing around like a headless chicken himself. :P Why is the

Yea, it's a bit funny to see somebody complain about headless chickens, and then go straight into dancing around like a headless chicken himself. :P Why is the difference between collision and preimage so difficult for people to understand...? I'm genuinely puzzled.