There may be some overlap in some denominations I'm not aware of, but as far as the Eucharist is concerned, it's largely only a Catholic thing. In Catholicism, the first Eucharist has a particular significance as Christ/the Spirit dwelling within you. In Protestantism, it's only an ordinance, so is only a representation/ritual/tradition. There is often a component of confessing sins privately before partaking though, but the "Lord's Supper" (as it's called by most protestant denominations) is not a means of grace or sacrament in most protestant denominations. By "means of grace", I mean that taking the Lord's Supper does not lead to salvation or impart God's grace or anything else. It's purely symbolic in probably 95% of Protestantism. In the other 5% of orthodox Protestantism, it's not just symbolic, but is not a means of salvation/grace. In Catholicism (to my understanding of not being Catholic but studying it in a protestant seminary), it is considered a means of grace and imparts some form or measure of grace for salvation.
In all of Christianity though, there is an understanding that our sin is a failure to live up to God's holiness and standards, and that in Protestantism one of the pillars (5 solas) is that it is only through his grace, mercy, and love for us that Jesus came to die, and that our salvation is due to his grace alone and not something individually inherent in ourselves that makes us worthy.
I'm hedging all of that with the fact that there's a lot of religions/denominations/cults that call themselves "Christian", and many believe very different things.