The typo in the original post is significant. In order to understand the sentence, one has
to understand that "make most of us" is a verb ("make") followed by a noun phrase ("most
of us"). In contrast, "make the most of" is -- as a whole -- one idiomatic verb phrase. The
object of "of" is "what," which is positioned, in surface structure, at the beginning of the
free relative clause ("what the least of us make most of us feel the least of us make the
most of"). "Life" is identified with "what." Quine's sentence is a WH-cleft (or pseudo-cleft).
The least of us make most of us feel the least of us make the most of life.
WH-cleft: Life is what the least of us make most of us feel the least of us make the most of. (Quine)
Compare: Mary makes Paul feel she likes flowers.
WH-cleft: Flowers are what Mary makes Paul feel she likes.