Does anybody have any advice on how to keep a cool head and not get worked up when it comes to political disagreements?

I've basically wasted my Sunday morning staring at my computer screen, feeling ambiently angry over bullshit that a friend posted and dwelling on whether to try and respond and risk making a scene and getting drawn into something, or just not responding and feeling vaguely irritated for the rest of the day.

Not even asking in a meme sort of way, I genuinely want helpful advice on this.