Someone who is saved is someone who has "confessed all their sins" to Jesus and thinks of Jesus as their ultimate savier and such, so they will go to heaven and not be a sinner anymore (someone who apparently will go to hell if he/she does not confess their sins to Jesus Christ and accept him as their ultimate savier]].
According to religion, once you're saved, you aren't allowed to cuss, fight, or do anything wrong whatsoever, so it makes the person feel kind of limited to living their life to the fullest.
1. This article has been considered to be pretty sure. If you find the time, please make it longer than it already is.