I ruined part of another player's Minecraft world.
Why would you destroy his Minecraft world?
Because I don't want him to succeed in the game.
You shouldn't ruin people's hard work. It's really selfish. You should find ways to create a better Minecraft world if you're jealous of this player.
I'm mad and I don't feel like doing anything else right now.
That sounds like really immature behavior. Maybe you should refrain from playing multiplayer games if you get angry and destroy things that belong to others?