After Ruby's collar got hung up on a decorative pillows fringe, I stopped having her wear one. As far as getting Max to like his collar you could try what I did to get Ruby to enjoy wearing clothes (she reacted to them like your Max is to collars).
Villette on the forum suggested when I put a dress on her to just make over her and tell her how pretty she is wearing her dress. I would tell her "what a pretty girl she is" and that her "Daddy would just love that dress on her", things like that. Sure enough it worked. Now, all I have to do is ask her "Ruby do you want to wear a dress?" She gets all excited and runs to me, sits down so that I can put it on her.
Do be careful with those collars though.