Why do we need to go to Confession - can we not just confess our sins straight to God?
It is a good question. Well, that's the way Jesus set it up on Easter Sunday evening. If we remember, then he told his apostles that just as God the Father had sent him — and God the Father sent him to save us from our sins — so he was sending them.
He breathed on them the power of the Holy Spirit, giving them God’s power to forgive sins, since no one can forgive sins but God alone. He then told them that whatever sins they forgive are forgiven and whatever sins they retain are retained. Check John 20:22
Of course, as the apostles couldn’t read minds, the only way that they would know which to forgive and which to retain is if people actually told them their sins. So really this was Jesus establishing the essential structure of the sacrament of reconciliation.
Just as he uses priests to give us his Body and Blood at Mass so he uses them to give us His mercy in the Sacrament of Penance - in Confession.
Plus, there's undoubtedly a huge value when going to Confession in actually hearing self vocalising what we're sorry for, and a huge value too in hearing the words spoken by the priest - 'through the ministry of the Church may God give you pardon and peace’......and....’I absolve you from your sins'
I like this Pope Francis quote ~ "Jesus in the confessional is not a coin operated launderette. It is a meeting with Jesus. He is waiting for us and accepts us just as we are".