Telemetry, but I don’t know if many Linux user doesn’t turn it off. But I also don’t know if many Linux user doesn’t fill bug reports.
Also, if you use Fedora you may recommend it to people that will leave telemetry and/or file bug report. And you also contribute to make the red hat ecosystem relevant, potentially bringing paid customers for RHEL. It’s a drop in the ocean of course, but personally I don’t want to contribute to it.
My great grandfather who refused to eat maggots-free cheese for some reason.