My father used to say that to me all the time. Whether it's a hand or power tool...both have serious potential to injure or even maim. Whenever you hear about someone injuring themselves when using tools, they are either using the tool improperly, or they forgot that one simple rule, and the blade made contact with a body part (usually a hand or finger) that was left in the path of the tool.
I have never "seriously" injured myself, and I have worked with all sorts of tools. Since moving to the condo 2 months ago, I have injured myself twice.
The first was when I was hanging my bicycles in the shed that turned out to belong to a neighbor..so to add "insult to injury", the work I did in the shed was meaningless. I was bending one of the hooks to try to open it up so the bicycle rim could slip in and out of it more easily..I was putting a lot of pressure on it with my hand, while it was locked in a vise, and it snapped...because it was a casting and not meant to be altered...my hand went flying across the clamp and I put a minor slice in the fat part of my thumb, which took a good week or two to completely heal.
Last night I was adding beams to my "bicycle bay". I was working over my head, and using a heavy drill with a phillips screw bit...driving in a 3" framing screw..but I was holding the screw and my finger was right next to the screw. I was pushing hard...the bit came out of the head of the screw and drove deeply into my finger. I think it only stopped because it hit bone.
Today its swollen, slightly painful, very stiff, and oozing a bit. Yes, I cleaned it thoroughly at the time..I'm going to get a tetanus shot and start antibiotics..but this is going to slow me down for at least a few days. All because in my haste, and due to a momentary lack of attention, all ten fingers were not behind the blade. Even though it wasn't a blade..same idea.