1) Sancho Panza is a poor laborer who is persuaded by Don Quixote to become his squire and join him on his adventures.
2) As a sensible, pragmatic man, Sancho Panza provides a realistic counterpoint to Don Quixote's idealistic and overactive imagination.
3) Their interactions showcase the contrast between Don Quixote's chivalric delusions and Sancho Panza's down-to-earth perspectives.