If you have an f/o who's stubborn or holds other people's opinions in low regard, imagine being one of the only people they will listen to.
Even if they're upset, or angry, or caught up in excitement in their own ideas... The moment you speak up, they pause. Their expression softens the moment they hear you, subtle enough you almost miss it. They listen, brow furrowed in thought, and whilst you speak you can tell their turning your words over carefully in their mind.
They might ask follow-up questions, try to sway you to their side, or even disagree completely: regardless of their response, it's clear from the way they behave—speaking to you directly and as an equal, a level of respect often withheld from others—that they take your thoughts and feelings on the matter incredibly seriously.
Where others' opinions are immediately dismissed, scorned, or plainly ignored, yours is held with care, valued just as highly as their own. After all, you're one of the few people they truly trust and believe in. Their faith in you is not to be taken lightly.