I like bun fight. Conveys the sense of a squabble where nobody is showing themselves in the best light very nicely. My mum always used it in reference to things like busy sales or certain shops where the customers maul the goods in an undignified fight for bargains, so not an mn thing for me.
The ones I hate most are anything to do with big girl pants, hoiking up judgey pants and instructing people to give their heads a wobble. All condescending and inflammatory, all infantile.
Also grim, eww, vom, vile, gross, etc., on competitive cleaning and laundry threads. Makes the poster sound unbearably prissy.
The fashion for swear words combined with cutesy nouns that was around a few years ago - cockwomble, twat badger, etc. Either swear or don’t. Mixing it up with tweeness is nails on chalkboard for me. People used to come up with new ones which other posters found hilarious. That was rather tedious.
All the above also annoy me for being examples of adults talking childishly. I’ve got no time for that.
Finally, ‘tone deaf’. Perfectly good phrase, but much over-used on mn. Often just means the poster using it disagrees in a particularly self-righteous way.