something that is objectively unnecessary but gives comfort or at least the illusion of comfort
i think of it like the laws of diminishing returns
think of a shitbox $3,000 used car. assuming the engine is more or less running, you get like 80% of the benefits of a car
it gets you from point A -> B - the primary purpose of a car
then you spend another $10,000 for a $13,000 5~6 year old Toyota or something. now you have A/C, that gives you an extra few % benefits. You get a carplay so you have a nice little screen for a GPS, another few %. you get a key that unlocks your car, etc.
so you went from 80% to lets say 90%. but that base 80%, getting you from point A -> B hasn't changed.
that extra $10,000 bought you 10% extra
then let's say you spend another $100,000 for a $113,000 car
you get all the benefits of the previous cars, but you maybe can speed up a little faster. you have heated seats. you have a sport mode or something.
that extra $100,000 bought you another like 7% so now you're at 97%
Luxury is that last 20%. The closer you wanna get to 100%, the more expensive each % costs. This is a status symbol