On this page we have some bad outcomes; Tool meets human. Each of these happened when the operator wasn't expecting to get hurt....

This accident occurred while someone was using a small (4" dia.) hand-held circular saw. The saw kicked-back probably when the operator hit something ridged (nail, tile,...?)
This is the same injury. You can see where the blade sliced into the thumb, cutting through the bone, but missing the tendons.
This dude was very lucky! An unexpected sneeze produced just a nick from the table saw