In Of Mice and Men, Curly's wife likes Lennie so much not only because he "beat up her husband", but also because he represents to her an opportunity to "spread her wings" so to speak.  In spite of all her short comings, she is, above all else, a very lonely woman, one of the few females in the predominantly male setting.  All of the other ranch hands know that Curly's wife is bad news and off limits, but Lennie is not as quick witted as the rest and is not able to  make this same conclusion.  To him, even though he has been told by George to stay away from Curly's wife, Lennie, too, is in need of a friendly face and a kind word.  For a bit it seems to be a mutual attraction to friendship; however, it sadly comes to a tragic end.