If that's your say so
A response to someone's stated opinion or position that, albeit inaccurate or even goofy, you just don't see the need or wish to argue it's merits.
Margie: I really enjoy watching The Bachelorette show, but I feel so sorry for the bachelors that get rejected - it so sad!
Me: If that's your say so, okay....
Me: If that's your say so, okay....