Can anyone please add to this list of excuses for not writing an ebook?

I know next to nothing about the Kindle market and how it works. I've never dabbled with Kindle, I was talking about eBook marketing in general and what seem people face. I haven't really been into the business of selling my own informational products for years but I'm thinking about getting back into it.

As far as I know, Kindle only allows people to refund eBooks within 7 days and it's meant for people who accidentally bought the wrong thing. I need to read up on this Kindle market and perhaps put some story telling/writing to the test there.