What is personally your favorite insult or what is the best comeback you've heard that destroyed someone?

I always thought motherfucker was a weird exclamation. At least right now, it doesn't fit with modern concepts of humiliating put downs because things like "I fucked your mum" are commonly understood phrases of contempt and ways to embarrass or domineer someone yet it creates the uncomfortable paradox of the person calling someone a motherfucker inadvertently placing their opponent in a rhetorical position of dominance and power over at least someone whose mother they have fucked, and quite possibly even the mother of the person calling them a mother fucker if they're happy to turn the tables and make that claim. Whether the term might once not have had those confusing connotations before common tropes around fucking of people's mothers being a dominance thing someone might take a chauvinistic pride in; within current culture, it definitely does.

Then you have the fact that statistically, quite a lot of normal people are going to be motherfuckers including everyone's Dad and especially the father of the person calling someone a motherfucker, so it's offensive impact is up against the heavily diluting effect of the sheer banality of the status of motherfucker. It's almost like saying "oxygen breather" and expecting to offend.

Then it gets so contextually muddied by the fact that the word has become semantically very flexible. I think I've even heard it used as a term of endearment before, at the very least it can sometimes be a stand in for just "people", as in "some motherfuckers like to smoke" wherein such cases it's fairly neutral in affect or at least only mildly negative. It's also used just as an exclamation of surprise or anger with a situation, this is actually where I most find myself using it. It's sometimes used with regard to objects, rather than people with which one is frustrated, a usage that I guess isn't so far removed from the original offensive intent but still broadens the scope somewhat. This flexibility isn't necessarily bad, after all "fuck" is extremely flexible and people will infer intent from context pretty effectively but again it does seem to me to sort of dilute it's antagonistic and offensive qualities by becoming mundane.

I guess the term works quite well because it's rather graphic. It doesn't just require the word itself to be arbitrarily considered offensive like "fuck" does, but instead produces mental imagery that's shocking and explicit, maybe that's how it's managed to hang around so long despite semantic ambiguity and possible rhetorical backfiring but for me, I still think it's a weird term. It's so ambiguous, and so tied up with weird ideas around propriety and women that make it feel strange in contexts where someone wants to be threatening and vulgar. It feels like a strangely dandy and out of place anachronism in the sort of 'street' context that I think people want to evoke when they use it. Feels like something I might expect people to say right before slapping each other with gloves. Are they upset with the person's habit of fucking mother's because it implies they're a philanderer? Would that be offensive to them? Or is it the mother they're supposed to have fucked who's improper? A "slut" for allowing the mother fucker to fuck them? If so, why is the issuer of the term directing their distaste at the mother fucker and not mother whom they fucked? Are they suggesting the person so-called, fucked their own mother? I guess that could make sense, a bit weird but certainly insulting, yet I've really never heard that that was the intended idea.