Why does Goodman Brown say, "Of all nights in the year, this one night must I tarry away from thee," and why does he feel he must journey "twixt now...

At some point
in our lives, all of us must leave our "F/faith" (innocence/naieve understanding of
the world) and go on a journey into "darkness" /ambiguous reality ("twixt now and
sunrise").  On this journey we learn, among other things, that all is not as we thought. 
This is particularly true in Brown's case of the people he knew and held in unrealistic/naieve
esteem.   He thought they were angels; they were only people.  Of course, we don't know if any
of the people in the story really were that horrible; the story seems to suggest that they were
not, although there are realities mentioned that are horrible such as being the only witness as
a maiden buries her child.

These "realities" are part of life;
things are far from perfect.  Without real evidence of anyone's failings (remember that the
night is as likely a dream as a "reality"), Brown judges them for being less perfect
than he needed/wanted them to be.  Instead of growing in his F/faith, he becomes paralyzed in
an...