Don't run with scissors.
I'm pretty sure it's a warning exactly nobody takes seriously. I mean, sure, children probably should avoid the motion + sharp objects equation, but we grown ups ought to be able to handle it, right? As long as we aren't simultaneously making stabby motions with them?
Not me. At least, I assume not--I haven't actually had a run-in with scissors yet. But last week, I split my thumbnail smack down the middle with an apple slicer. Two weeks ago I took a chunk out of my index finger when I was chopping vegetables and missed. I have a nasty scar on the knobby bit of my wrist from when I juggled a razor in the shower.
If scissors are a gateway cutting tool, I've skipped straight to the hard stuff.
(True: Super glue is a useful tool to have in one's first aid kit.)