I believe no happiness can be found worthy to be compared with that of a soul in Purgatory except that of the saints in Paradise; and day by day this happiness grows as God flows into these souls, more and more as the hindrance to His entrance is consumed. Sin's rust is the hindrance, and the fire burns the rust away so that more and more the soul opens itself up to the divine inflowing.
Others - including St. Faustina Kowalska and St. Stanislaus Papczynski - describe Purgatory in often frightening terms. In one account, following a profound mystical experience of the Holy Souls in Purgatory, St. Stanislaus told his confreres, "Pray, brethren, for the souls in Purgatory, for they suffer unbearably."
So which is it?
To address this apparent discrepancy, first let me say that I find it helpful to equate Purgatory to radiation treatment. Some people view radiation treatment as simply awful. Others see it as a positive - because it will eventually render the patient clear of disease. The reality, of course, is that Purgatory is a positive thing. In Purgatory, the fire of God's love purifies souls of their attachment to sin. It cleans away the dross so that souls may enter into Heaven.
Another thing to keep in mind is that the descriptions we read of Purgatory may differ in degree of harshness simply because different souls require different degrees of purification based on their sins. In other words, some need a little more radiation than others. Along that line of thinking, St. Frances of Rome is among those mystics who were given visions of different "levels" of Purgatory. She described the lowest level as like a vast burning sea; the middle level as less rigorous; and the highest level consisting of those closest to their release into Heaven.
The bottom line is, God did not reveal the state of the souls in Purgatory to His saints in order to frighten us. Rather, He did so in order to fill us with hope that Heaven awaits those who die in His friendship.
