What is the importance of decentralization with cryptocurrency?

I’m a newcomer here. As in, I’ve been in crypto for like a year. I got into it because I made money off of Doge coin, I wanted to find the next Doge coin, I found the next Doge coin (from my perspective), and it went well.

So then I got into crypto as a whole. But, I see a lot of sentiments flying. One of which is the importance of decentralization. What is the importance of decentralization with Cryptocurrency? How come some people dislike centralized exchanges? These things are certainly new to me, and I would like to understand.

I’m not sure if I’ve hit a high enough text length to post, but I hope so.