A good carpet does something a rug never quite manages, it warms a whole room from the floor up so the air itself feels softer. Walk across it barefoot on a cold morning and you understand why anyone bothers. Sit on it with a laptop, let a kid sprawl out on it, and it just absorbs the day in a way hard flooring never does.
That said, carpet is not the right call everywhere. Bathrooms, obviously, and I'd think twice in a kitchen too, since anything that drips or spills sits in the fibers rather than wiping off a hard surface. Mudrooms and entryways are a bad match for the same reason, all that grit and wet grinds in at the door before you've gone three steps. If you've got pets who shed heavily or anyone in the house with allergies that flare in spring, a wall to wall carpet in a bedroom can work against you instead of for you. Basements need a hard look too, since carpet over a slab that gets any dampness at all will hold onto that smell longer than you'd like.
It also clashes with a certain kind of furniture plan. Rolling desk chairs fight it constantly, you end up with wheels that drag and a patch worn thin within a year. Heavy furniture with narrow legs, the kind that needs to sit dead level, doesn't love a thick pile either, everything tips slightly and never looks quite settled. And if you already have a room full of pattern, a patterned rug on top of patterned curtains, a carpet with its own busy texture or color is one layer too many. It starts to feel like the room is working against itself rather than with you.
On color, I've learned to be boring on purpose. Lighter neutrals, a warm gray, a soft oatmeal, anything in that tan to greige range, hide less than you'd think day to day but photograph and live calmer than anything darker. Dark carpet looks rich in the showroom and shows every speck of lint and dust within a week at home. I made that mistake once in a guest room, loved it for two weeks, then spent every visit before my mother came over running the vacuum like my life depended on it. Mid tone neutrals split the difference best, forgiving enough for daily life, still calm enough not to fight your furniture.
The detail that actually sells me, every time, is how a good one feels under bare feet first thing, before coffee, before anything else has gone right that morning.