One of my pet peeves about modern preaching and modern pastoral counseling is the complete ignorance of many preachers/priests/pastors when they throw in what I call "pop theology." Like its cousin pop psychology, pop theology is theology that is taken from greater popular culture and usually applied haphazardly and erroneously. Usually this bit of well intentioned "pop" information is usually devoid of any actual academic underpinnings or substance. It is simply what is popular, and what is popular is usually not academic heavy lifting or really all that helpful in the grand scheme of things. In fact, pop theology is usually unhelpful and trite.
One of those things that gets under my skin is when preachers or pastoral counselors try to apply the pop theology understanding of St. John of the Cross' Dark Night of the Soul. Dark Night of the Soul is a quite long poem (often in 2 volumes) steeped in Christian Mysticism and Catholic theology of perfection of the soul. John of the Cross was writing it when he was imprisoned by his fellow Carmelite religious order who were attempting to force him by hook and by crook to recant his calls for reforms of the order.
Pop Theology has turned the premise of the Dark Night of the Soul into a euphemism for some deep "rock bottom" spiritual crisis or spiritual depression when it seems like God is not there. That is completely wrong. If you hear a preacher or counselor using the term "dark night of the soul" in this way, they have obviously never actually read John of the Cross' Dark Night of the Soul. (For those who have not, you can read or listen to the entire thing here.)
Now, I do not claim to be a John of the Cross scholar. In fact, there is a lot that the actual work touches upon that is over my spiritual and theological head. It is an extremely heavy work of theology in its own way, but I have read it and know enough to not demean the work by using the term "dark night of the soul" in the pop theology manner of using it.
I bring this up because Dr. Taylor Marshall did an excellent little blog about understanding the difference between the Dark Night of the Soul and the Dark Night of the Senses. Both are part of John of the Cross' journey in that work, but they are two separate concepts that need to be understood.
Saint John of the Cross' poem narrates the journey of the soul from its bodily home to its ultimate union with God. The journey is called "The Dark Night" because darkness represents the hardships and difficulties the soul meets in detachment from the world and reaching the light of the perfect and eternal union with God. There are several steps in this night, which are related in successive stanzas. The main idea of the poem can be seen as the painful experience that people endure as they seek to grow in spiritual maturity and union with God. Catholic views on Purgatory are extremely important here because often humans while they are living cannot achieve this sort of "Dark Night of the Soul" until they physically leave the physical world and begin the final process of perfection and sanctification, oftentimes in Purgatory according to Catholic theology.
So, when you hear someone referring to having a Dark Night of the Soul, and they are using it simply as a euphemism for some "dark period" of their personal life that is not leading them to rejoice in their sufferings that lead them to final perfection and ultimate union with God, then chances are they are not understanding what John of the Cross is really talking about.