it's not really what happens in canon as far as I can tell but I'm rotating the idea that when Chopper joins the crew and starts desperately people-pleasing and allowing himself to suffer thinking that's what it takes to be accepted and loved, something in Sanji goes "O h ." and he starts making an effort to show Chopper very clearly that the love from this crew is not conditional. and maybe a little bit (a lot), he's saying it all to make himself believe it, too.