- “Purgatory is a place where souls who don’t deserve heaven get a second chance to be with God”;
- “Purgatory is the best that I can hope for in the afterlife, since heaven is only for really holy people”;
- “Purgatory is a place where souls work their own way into heaven, since God’s grace is not enough.”
We can die in unity with God but still have imperfections on our soul. These include things like venial sins, concupiscence (the inclination or propensity to sin), attachments to sin (the state of finding certain sins attractive or appealing), and insufficient reparation (the state of not having adequately made up for the negative effects of one’s sin). Since heaven is a place where no unclean thing shall enter (cf. Rev 21:27), God desires to purge these things from the persons who die in union with Him.
The first description is a misconception because Purgatory is only for souls that are already in a state of grace or friendship with God. These souls have persevered to the end. The divine life in them remains. If a soul is not fit for heaven, then it is not fit for Purgatory. There are no “second-chances” in the afterlife.
The second description is a misconception, first of all, because Purgatory is not a final destination. Souls don’t go to Purgatory and stay there forever. Eventually, they move on to heaven. Secondly, Jesus Christ did not die on the Cross for a select few. No, He died for all mankind (even you!). Our hope should be in heaven, and in the power of God’s grace to actually get us there.
The third description is a misconception because it attributes a soul’s release from Purgatory to his own suffering, instead of to the work and suffering of Christ. Yes, there is suffering in Purgatory. After all, it is a state of being refined in the furnace that is the burning fire of God’s love (cf. 1 Cor 3:12-15; Heb 12:29, Songs 8:6). We certainly can’t expect that to be pleasant! But, our suffering only has meaning and is only meritorious (or, worthy of receiving grace) because of the grace of God. Purgatory is a final application of the grace that He won for us on the Cross. So, it is ridiculous to say that Purgatory is somehow a belittling or a contradiction of that work.
I hope that helps you to understand Purgatory better. For more on Purgatory, see the Eschatology and the Last Things Topical Index Page.