I don't think my writing is up to par today, but I wanted to respond. Also, I'm not over 40.
Sometimes I wonder if a midlife crisis is synonymous with an existential crisis. I'd think they have ties that bind them, but maybe they're separate parts of the same "crisis" element. Maybe existential is more abstract, and mid-life is more here-and-now based. Anyway, I think I had several when I was about 24 or so, continuing to my current age. After I got through college and got into the work force, I started looking more at my own life and the underlying nature of it. Once I asked one or two questions and found that there weren't any answers available (questions that people have been asking for centuries), I couldn't just "forget about it and focus on the day to day realities."
While my friends were concerned with how much money they were making, when they'd be able to get a place of their own, how'd they promote, how they'd get through college, what others were thinking about them and how to maintain a positive image in their group of friends, higher ups, and the opposite sex - I started to disconnect and get more focused on the whole context of it all. I started feeling things quite similar to this (starting at 47 seconds):
[ame="http://www.youtube.com/watch?v=ERbvKrH-GC4"]YouTube - Music and Life - Alan Watts[/ame]
I started asking abstract questions like:
"If I was born not knowing where I came from, and I'll die without knowing where I'm going, then what does it really matter what I choose to do with my life - whether it be pleasurable or displeasurable to myself or anyone else? Whether anyone approves of it or not?"
"If everyone else was born as unknowing as I was, then why the hell should I respect people with titles under their names and their assertions that certain things are good or evil? Do good and evil even exist? Would good and evil exist in a universe where life didn't exist - where there were only swirling planets and suns? Would the universe think that it would be good or evil if a sun exploded or if it burned forever? Do animals apply to a universal good or evil, if it does exist? If yes, then it's dumb because you can't get mad at a lion for killing a gazelle or an alligator for eating it's own young - it's in it's nature. If no, then are we to say that a man is evil if he is compelled by his nature to do "abnormal" things like kill others or take advantage of others or be cruel or lie? Is it our own subjective interpretation, and the general concensus of feelings about a subject defines the law and rules governing that subject? Well then, what should I do if I'm not IN that general concensus?"
and "If the good life today consists of having these luxuries such as air conditioning, a car, vacations to far away places, stucco'ed walls and aluminum siding, a cell phone, and internet access, does that mean that nobody before the 1900s (or when those things were respectively invented) had good lives, and that they weren't happy? And if they were happy, then why should I or others need them in order to be happy?"
and seriously asking those religious questions that get dismissed like "If God (exists and) is all knowing, all powerful, and all good, then why is there evil, misery, and sorrow in the world?" and "Why did God intervene in the past and speak to people (if he, in fact, did), but he doesn't anymore?" and "Why would God have created us in the first place? What possible reason could he have?" and "If God made me and I am naturally doing things he disapproves of, whether they are subject to my nature (which he created) or the environment that my nature must exist in (which he created), then why the hell would he get mad at me for doing anything at all!"
and the ever-potent unanswered questions like "What am I supposed to be doing here, or is there nothing I'm really "supposed" to be doing?"
And whenever I'd ask other people those sort of questions I got a response similar to when a child incessantly asks "Why?" to get to the point of the base reality behind it all. That is "That's just the way it is!"... or reasoning like "It sucks to be poor!" as if that's the end-all-be-all of it. That doesn't satisfy the mind, however.
Getting to the application point of it all, which may be more along the lines of a mid-life crisis, the question might be "Why the hell have I been following people around and not doing the things I want to do in my life? Why do I have this need for acceptance and social relationships that trumps my ability to do what I want to do? Why have I been living a life that others think is good instead of doing the things I want to do? This is MY life and I should live it the way I want. If that means indulging, taking drastic measures, doing things that others disapprove of but I take great value in, then I should indulge, take drastic measures, and doing things that others disapprove of but I take great value in. But maybe I shouldn't because others won't approve and I'll starve to death."
Hmmm...