That Conundrum

Well, you know the type, generally
referred to as reserved in temperament.
The kind of person who always seems to
have a supercilious hint of a smile flickering
over a face that's otherwise hard to read
a really annoying trait that doesn't tend
to rouse confidence in the casual but
frequent acquaintance. Exemplifying
in fact the kind of personality you prefer
to acknowledge with a quick smile and a
swifter but polite parting. Something most
definitely off-putting about such people.
They don't seem to gain much in the
company of others, sufficient unto
themselves, you know? Well, you think
you know and you may be wrong. They
may be self-contained and that might be
because of social awkwardness and a
sense of not 'belonging' whatever that is
to whoever feels that way, an uncertainty
you don't share. And then the day comes
when the facade slips and a torrent of
confessional intimacies inundates the most
casual of passing conversations and you
stand there, an unwilling and confused
confidante until the realization dawns that
this person whom you've meant to avoid
whose presence makes you uneasy and
whom you don't think much of is really
another person in need of a friend to 
confide in. What's your response? Will
it make any difference, misjudgement?