My mum's always coming out with really obscure Scottish sayings that her mum used to say but for the life of me, I can't think of any at the moment.

I'm seeing her in a bit so if I remember, I'll ask her.

But.. to continue with the 'agree to disagree' theme in your OP, here's a few of my own favourite sayings to be going on with:

A quiet tongue shows a wise head

You can't shake hands with a clenched fist

A quarrel is like an itch; the more you scratch, the more it itches

It takes two to make a quarrel but only one to end it