The relashionship between Curley and Lennie in part 2

One thing that stood out to me in part two was the relashionship between Lennie and Curley. As Curley walked into the picture it was clear to me that he didn't like Curley, I couldnt help but wonder ... was it jus that he was small and short and Lennie was big and tall or was there something else behind their relationship. The author is yet to answer my qustion so I am going to try and figure this out ! I couldn't help but notice the tension between them. On page 26 Lennie said "' we jus' come in"' Curley responded with "'Well, nex' time you answer when your spoken to."' It felt as if to me that they had known each other before this interaction judging by what they said and how nervous Lennie was just to be around him. There is a chance that this is just becuase of his mental illness but it is not clear. As a result I belive it could lean either way. Did anyone else notice the tension or thought the same?