There's a special breed of "conversation" that happens sometimes on Tumblr. There are scare quotes around that for a reason, which I'll get to in a second. "Friendly reminders" sometimes espouse decent views or tidbits of food for thought that are genuinely worthy of consideration, but more often than not are wrapped up in so much poisonous passive aggression that it completely kills whatever point the post might have been bringing up, at least for me.

More annoying than that perhaps is their propensity to come across as sounding so authoritarian.

I don't know who you are, person issuing this 'friendly reminder,' nor what your motivations are, nor what your qualifications are for dictating things to me in such an insulting and condescending way. It's seen so often as being this snappy, witty thing, but I just find it acerbic and offputting. The concept of tone argument can only be taken so far. Righteous anger can only be so useful in meaningful discourse before it starts polluting everything it touches.