I hear you and I envy you for your control. I'm constantly working on keeping my mouth shut on certain topics but then I slip and let it out anyway. Not everything has to be said at all times and sometimes keeping your mouth shut is more productive than not. It's also better for your own mental state.

Plus, most people can't agree to disagree. You're either with them or against them. Very few can disagree on a topic and still be (online) friends. It's part of the whole tribes and factions shit.