Una sopa de su propio chocolate. Yes.

No. It's a matter of style and self expression.

Better is it to treat them always better but that can be so very difficult from time to time.

Yes

...I'm not so sure. I get the sentiment on the positive end... but to treat every arsehole it a bad was sounds exhausting.

Nah, mostly not. I do not like to be treated like a turd, but I hate it more to be a revenge turd.

"Treat people according to how you are, not how they are" (paraphrased because I can't remember exactly how it went). What Sean said. Treating shitty people shittily won't teach them a lesson or make either one of you a better person, it'll just add more toxicity to the cesspool we call humanity, and probably reinforce their worldview of interpersonal shittiness.

Fo sho

Nah, but you can make it known if you disapprove of how you are being treated