Do people realy care about the story in custom storys?

[Kreekakon]

Depends on what you're asking from yourself. Are you aiming to make your story a super detailed plot, or are you trying to make it a simple reason for why you do some things (This isn't a bad thing though). Look at what you initially want, and then go do it. Making games is/should be a form of art, and self-expression; do what you are seeking to express from yourself regardless of what you think the audience will think, and give it the amount of quality you believe the CS deserves.

Putting that aside...if the story is intriguing enough, I will want to pay attention to it, but this doesn't prove to be the same for everyone. Just look at Bioshock. I know some people who had no idea who Fontaine was until the big moment, but for people who are willing to pay attention, it's extremely rewarding.