It's definitely really hard to deal with refunds. You can make 10 sales in one day, but if there's only 1 refund, you might feel sad and disappointed.

About the reasons for refunds - you're right, many people buy without reading and then ask for refund later. Others might feel buyer's remorse.

In my case, the most common request was because of their personal taste. You see, I'm selling a theme for developers and they usually spend a lot of time using the same theme. It takes time to adapt to a new one color scheme, and some people ended up asking for the refund before they get used to it.