Nicodemus vs. the Samaritan Woman (John 3, John 4)

Nicodemus	Samaritan Woman
He is well-known	She is anonymous
He scrupulously keeps purity laws	She is permanently unclean
He is a religious leader	She is a religious outsider (even among Samaritans)
He is a great teacher of truth	She believes Samaritan heresies
He is a high government official	She has no power
He is morally respectable	She is morally suspect
He seeks out Jesus at night	Jesus seeks her out at noon
He knows that Jesus is a teacher from God	She knows that Jesus is a Jewish man
Jesus does not fully reveal himself to him	Jesus teaches her clearly that he is the Messiah
He does not understand the living water	She asks Jesus for the living water
He leaves lacking understanding	She leaves knowing who Jesus is
He hides his belief	She tells her whole town about Jesus

Notes:
Some rabbis believed that all Samaritan women were permanently unclean.
Jews viewed Samaritans as heretics: Samaritans only believed in the Pentateuch, which they had altered that to fit their beliefs, and Samaritans believed the correct temple was on top of Mt. Gerizim. There was also a history of violence between Jews and Samaritans.
Samaritans were probably not "half-breeds"; this view comes from assuming that the residents of Samaria mentioned in Ezra and Nehemiah are the same residents of Samaria mentioned in the Gospels. However, they are probably not the same people. First-century Samaritans are probably a sect of Judaism, which is how they regarded themselves.

Here are some more posts on Nicodemus; here are some more on the Samaritan woman; and here are all my posts on the Gospel of John.