What's the upgrade that stopped your house feeling builder grade?

People who moved into a place with the standard package, that's a question to you!

Beige paint, oak cabinets, those flat dome fixtures in every room. What was the first change you made that actually shifted how the house felt, not just how it looked in photos.
We hear lighting a lot, but the honest answer might be something else entirely.
It could have been paint everywhere, or new flooring, or just better cabinet hardware.
What was the one thing that made you stop noticing the builder grade and start seeing your house?