embitterment and stagnation? hmmm...
I think these "moments" could always serve some purpose in later life. Feeling of stagnation is just a feeling. Life goes on.
if perhaps "movement" is the key to progress
Positivistic 19th century continental thinking? Well, I'm not a person who's looking for some kind of linear progress. I guess my mind works differently. But then again movement is not synonymous to linear progress, so I may be understanding this differently. Pardon me if my understanding is different from what you've intended to say.
it's possible to be outwardly moving and inwardly stagnate
I think so too...
The anger and bitterness is more a projection onto others of feeling stagnate in one's own life.
I have experienced this several times over the last 10 years. (Bad childhood?) I realized it's not just stagnation, but sometimes it also involves vanity. We can be angry or bitter because we're not given due credit, enough attention, enough caring, etc. Like how can this be happening to the great me? Like a rich, former high-school honor student who suddenly found herself to be among the mediocre minds in the university, and that she's one of them. (I was never an honor student neither am I rich, thank god. At least, I do not partake of that horrible Asian stereotype). Or like a woman who always rejects men but got rejected by the man she actually pursued.
We feel life is being unfair to us - that life is cheating on us. But life is never fair. Prolonged anger and bitterness are perfectly understandable, esp for people who experienced war, rape, and all those horrible things - big or small - that could happen to a person. But I've seen bitterness taken to extremes in most simple situations. Sometimes I see bitterness in others (and in me) that were simply out of proportion that leads me to think -
Aha, that person is just being vain. Give him/her another person who will load up praises for him/her, s/he'll definitely get out of the rut.