So I've been working professionally with Linux-based systems for a few years, and while I'm not the expert I would like to be, I have got a pretty good feeling for the way those systems work. You have the bootloader, the initramfs, the boot procedure, systemd, PID 1, you can check the logs, you have all those little things that make the system work. Everything is a file, you have file permissions and selinux contexts, you have networkmanager, systemd units, you have (system) users, some just for some services, it's all dandy.. if I have a problem with a program I can usually debug it, check its logs, and get it to run.