Personally I think it is all about balance and sincerity.
Being nice to your partner is a good thing. Standing up for yourself is also a good thing. You can do both if you are both prepared to compromise.
Being sincere is also important. Don't sugar coat things. Be up front about what you really feel and don't pretend to like something when you don't like it. Don't compromise just to please them if you know you will resent it later. Sometimes you need to agree to disagree (I hate that cliche but it seems appropriate here).
I won't say never but it's extremely unlikely two people will be 100% compatible and always agree on every single detail. Good luck if you are those people.
Being nice to your partner is a good thing. Standing up for yourself is also a good thing. You can do both if you are both prepared to compromise.
Being sincere is also important. Don't sugar coat things. Be up front about what you really feel and don't pretend to like something when you don't like it. Don't compromise just to please them if you know you will resent it later. Sometimes you need to agree to disagree (I hate that cliche but it seems appropriate here).
I won't say never but it's extremely unlikely two people will be 100% compatible and always agree on every single detail. Good luck if you are those people.