What’s a time when you didn’t realise how serious something was until after the fact?

Used to go to Reading Festival as a drunk stupid teenager. I always thought it was pretty funny when people would start really big fires, or throw their remaining gas cannisters on the fire before leaving on the Monday. I accepted it as being part of the rock n roll attitude of the festival or whatever. When I was 20 I worked there in the fire towers they have in the campsites. Our job was to either be up the tower looking out for fires that were too big, or at the bottom putting them out. Our training consisted of us sitting patiently in a marquee for half an hour or so before the manager walked in, pulled the pin out of an extinguisher, set it off in our general direction and said "there's your training. Get to work." We were supposed to put out any fire that was more than a pace wide, and call the on-site fire brigade for anything above waist height. That was a fucking joke because they all were too high and the FB were horribly over stretched. I ended up tackling fires that were taller than me, entirely on my own, armed with nothing but a ghostbuster style backpack full of water and a pump gun. People would throw cans and shout abuse at you for ruining their fun. One evening I saw a group of people carry a tent towards a massive fire, only for some guy to jump out of it at the last second before they burnt the whole thing up. The whole weekend was like this. I sat on the train home from that festival and my hands were shaking the whole way. The entire weekend had been so intense that I hadn't stopped and taken the time to really notice the situation I had been put in. I never went back there as a punter or a worker. This was a long time ago, I don't know if it's any better now. But at one point that whole festival survived on pure luck and a few overworked and untrained staff members that kept it just on the edge of breaking down altogether.