Knives are Sharp

Megan was doing some prep for her Art GCSE Exam, she had commandeered a stanley knife from the garage and headed off to her bedroom. "Be careful, that knife is sharp" I said.
Half an hour later she emerged with her hand swathed in kitchen roll saying she thought she had cut the top of her finger off.
It turns out it was just the side of her finger that got cut off, so no harm done. Apart from the MASSIVE hole in her finger that wouldn't stop bleeding for about 12 hours.
Lesson learnt?!