One time when I was in like 7th or 8th grade, some kid in science was fucking around with the test tubes. The teacher told him to go to his desk, so I sarcastically said "yeah, if you're not careful, you might blow up the school." She immediately went ballistic, saying threats like that were very serious and to go to the principal. Luckily, the principal was actually sane, and just sent me back to class.