Using “uncomfy” instead of uncomfortable. I recognize this one is fully style, but it’s like nails on a chalkboard. Break the entirely fake rules of grammar and spelling all you want, but have some decency when it comes to connotation.

Comfy is an informal and almost diminutive form (not technically, but it follows the structure so it kinda feels like it) of comfortable. You have to have a degree of comfort to use the less formal “comfy,” so uncomfy is just…paradoxical? Oxymoronic? Ironic? I’d be ok with it used for humor, but not in earnest.

Relatedly, for me “comfy” is necessarily referring to physical comfort, not emotional. I can be either comfy or comfortable in a soft fuzzy chair. I can be comfortable in a new social situation. I can be uncomfortable in either. I can be uncomfy in neither, because that would be ridiculous.

FWIW I would never actually correct someone on this. I would immediately have my linguist card revoked, and I can’t point to a real fake grammatical rule that would make it “incorrect” even if I wanted to. But this is the one and only English usage thing I hate, and I hate it very, very much.