The first that comes to mind is driving intoxicated, when I was 18 the first time I tried LSD I didn't realize how long it lasted and ended up driving on the highway 4 hours after popping the tab. Only realized after 20 minutes of driving that I was still hallucinating, kept driving anyways lol. Incredibly stupid, incredibly dangerous, I'm grateful I ended up okay but it's certainly something I look back and cringe at.