I tried answering a question very much like this one and as I wrote I got frustrated and quit. You listen closely to what the artists, producer and A&R want, then you sit down to mix. You ignore the ideas you don't like and keep the ones that work. If you want to defend your idea, show them the one they perferred, if it doesn't work, they'll notice it and it won't linger in the back of their mind. If they come in and say it's wrong, I listen to their reasons, say "ooh ok, I get it" come back in 30 minutes. I make it right, they come in happier than a pig in sh*t. If the band members are fighting among themselves or against A&R or Producer or any combination of the three, I SHUT UP. I don't say a thing and I don't interfere. When they turn to me to ask my opinion I simply say, "You heard my opinion when i played you the mix.I am not getting in the middle of this. Make up your mind and i'll make the change or I'll give you two versions and you guys can fight it out later". That tends to work like a charm.
Yes, of course I've had mixes rejected. We all have, except for the big fibbers of the world.