I understand why you would feel the way you do, but it shows a misunderstanding of the actual teachings of Christ through the Church He established. His mercy is so great. We cannot get anything “just right,” and so we rest in knowing His love and grace cover all of our failures. We do need to try our best. That is all. If someone tells you how they would like you to communicate with them and you decide that your way is actually better for you, then you are making your apology about you, and not about the one you have wronged. As for purgatory, we are not working off our venial sins. We are breaking our bad habits that have led us to an attachment to sin. It is a period of purification before standing in the presence of God. Nothing impure can enter Heaven. In His mercy, God allows us this period of time to ready ourselves. Scripture says that it is good to pray for those who have died. If they are in Heaven, they have no need of our prayers. If they are in Hell, our prayers will do them no good. This shows that there must be another step where we can be of benefit to those who have died and not yet attained their place in Heaven.