Is this all there is?

It can be dangerous to ponder the question "Is this all there is?" particularly after one has been doing life for over half a century and is firmly grounded in the middle-age.

Life moves forward every day and it's easy to thrust one's self into the routine, moving ahead because that's what we do. For the most part, I'm productively occupied and engaged in my day-to-day commitments; busy and sated by a sense of purpose. For me, it's my work. I work as if what I do is important. That it makes a difference on some grander scale. This likely is good as I spend a significant amount of time engaged in my work. To the detriment of other aspects of my life, perhaps.

So why the choice of the word "dangerous"? What's dangerous about this line of thought?