When I was, oh...6-7 years old, my parents bought everyone a fishtank! We all got a fish, and they lived in the same tank in absolute harmony.*cannibal sorry had to do it...
My fish decided to be a carnivore for the day, and ATE the other two fish.
Being the idiot kid I was, I thought I had the best fish in the world.
My parents didn't keep that fish.
Plenty of fish eat other fish. It's only cannibalism if they eat their own species/breed. Such is the food chain.
I think I was 4 or 5. I saw our neighbor had a dog chained up in their front yard, but their dog's chain wasn't tied to anything. Instead, the end of the chain was under a heavy piece of cement. I felt bad for the big doggie, so I went over there to try to free him.
You can kinda see a number of reasons that was dumb of me to do.
1. No one wants their dog to run away and get lost. I didn't think about the dog running off if he was free.
2. Some dogs are territorial, and that dog was much bigger than me.
I didn't think about that possibility, so it's a good thing he pretty much ignored me.
Luckily, the cement was too heavy for me to move, so doggie stayed chained up.