While I do have my carbon full suspension with all the latest and greatest on it, I find myself riding my rigid single speed just as often. I bought it with an 11 speed drivetrain, hydraulic brakes, and a suspension fork. I ended up selling all of that and setting it up single speed with mechanical brakes that I had laying around. It’s a little refreshing to have a bike that rarely needs maintenance. I also don’t worry about riding it in messy conditions, I don’t worry about damage being done to it when I crash, I don’t mind locking it up around town.
I did put a dropper on it right away though because that’s the most fun per dollar upgrade out there!