Mathematics: Momentous or Mundane?

Giving pause...:

Over the weekend Mike Lawler, posted about two items ("two incredible descriptions of what it is like to do math research") he wished he had seen in graduate school in order to maintain his avid prior enthusiasm for math (one is a Numberphile interview with Ken Ribet, and the other is Cedric Villani's current book, "Birth of a Theorem"):

http://tinyurl.com/q355eyo

The post contains these sentences that I find oddly-riveting about Mike's sudden loss of interest in math after a 5th-grade-to-grad-school infatuation with the subject:

"Towards the end of my third year in graduate school, though, I completely lost interest in math. It didn’t happen gradually, either – I just woke up one day and wasn’t interested in math anymore. I’ve never known why."

How bizarre is that??? But then I know that I too sometimes have flashes of wondering if perhaps mathematics is just a boring .00001% smidgen of what there is to know out there, and that real knowledge resides elsewhere in some metaphysical/paranormal/spiritual/mystical/other-worldly realm... the power of mathematics being but an illusion! A bit reminiscent of the 2nd Bertrand Russell quote I employ above:
"I have come to believe, though very reluctantly, that it [mathematics] consists of tautologies. I fear that, to a mind of sufficient intellectual power, the whole of mathematics would appear trivial, as trivial as the statement that a four-legged animal is an animal." ---Bertrand Russell (1957)

That was Russell summing up close to 70 years of philosophical contemplation. ...Frustration, or epiphany?
(Yesterday at Math-Frolic, I used quotes from Richard Feynman to stress that "UNCERTAINTY" is the hallmark of all our knowledge.)

On-the-other-hand, we have current-day physicist Max Tegmark arguing that ALL there is to the Universe is mathematics... ultimately, there is nothing else:



(Max's book "Our Mathematical Universe" HERE.)

Sometimes math seems like a Necker Cube, changing appearances when stared at long enough... penetrating and insightful one moment, trivial and mundane the next.

Anyway, I'm left to wonder, do other mathematicians experience the flashes of doubt and lapses in math-veneration of Lawler and Russell (and me), from time-to-time??? Or are these rare occurrences, from too much beer and pepperoni pizza? ;-)  Anyone...?