Why are there so many trade wars between countries? What is the effect on the world economy?

https://www.quora.com/Why-are-there-so-many-trade-wars-between-countries-What-is-the-effect-on-the-world-economy/answer/%E6%A1%91%E7%94%B0-%E5%81%A5%E5%8F%B8-Kuwata-Kenji?prompt_topic_bio=1

Isn't it because the organization that governs the world with gold is doing whatever they want?