Cammil Taank:
I feel I may have over thought this. It appears that the Dark Night is not debilitating, just unpleasant. I certainly do not mind going through a difficult period if I can still function at work.
I'm surprised nobody commented on this. It may not be debilitating, or it may be. It may be "just unpleasant" or it may be much more, or maybe even less. Gathering from what I've read of people's reports here and from people I've met in person, I don't think that there is any predictor as of yet which can tell you how debilitating or not your Dark Night experiences will be.
I don't see any reason not to be have some preparation for a worst case scenario. Since your concern is work, these are the things from my own experience which may be debilitating:
1. Physical pain, agony, fatigue, lethargy. If physical side effects come up, you may not have as much energy or strength to accomplish as many tasks during the day. You may need to spend more time in bed, or taking bubble baths, getting massages, or just relaxing.
2. Emotional reactivity, and projection. If this stuff comes up, you may end up unloading on some poor unsuspecting colleague or boss, etc.
3. The insights themselves. I think this may be the trickiest one of them all. You will be having profound insights into impermanence, suffering, and non-self. One way this may translate: Impermanence... Your job: it's just a flittering spark coming and going for a brief moment on the surface of this vast and infinitely deep universe. Money? It comes and goes, you can never hold on to it. It never lasts forever. Suffering... The rat race of chasing this, chasing that... you're whole life you've been chasing objects of the world, and for what? As soon as you get them, they slip away. No-self... You don't own any of this. Money isn't yours to possess. You aren't your job title, you aren't your so-called "successes", your self-centeredness has gotten you nowhere.... etc... etc... Do you see where this is headed?
Number 3 is tricky because you may be so caught up in a new illusion that you begin to intentionally destroy areas of your life. How would you carry on with your job if all of a sudden it seems to be completely insignificant, transient, impersonal. If you had no idea why your doing it or why anyone would do something like that and it all seems so pointless, what would you do? could you just keep going with it?
There are ways to deal with this stuff and remain functional (some of which have been suggested in this thread already). And, it seems to go easier for those who are prepared and informed so that they can recognize "oh, this is the Dark Night, I won't take it to seriously."
On another note, I think other parts of the path can also be debilitating. The A&P can hit like a manic attack. You can imagine how annoying the born-again religious type people can be. This sort of evangelical, manic, overly-enthusiastic mysticism can be quite disruptive as well. I'm sure I alienated lots of people by telling them how I had figured it all out and how I was a buddha and whatnot.
As an anecdote, I had a friend who one day decided to try this sexual energy meditation that he read about. He crossed the A&P and then started going to parties all the time on lots of drugs with a bible and he would freestyle rap bible sermons for hours and hours. No one knew what the hell was going on with him, although I recognized it because I had crossed the A&P a year or two earlier (but, still I had no idea what exactly it was either). People thought it was cute at first, but after 6 hours of beligerant freestyle rap of the old testament and various mystical/spiritual themes, people got pissed off at him. Eventually, he sorta disappeared (as he hit the dark night), and a couple years later I heard a report that he was in prison. He was definitely weird to begin with, but at least he had been functional for his whole life before that point.
While there's no way to know what you'll go through, and it may be super easy, I think it's worthwhile to know about the other possibilities.