The "systemctl soft-reboot" #systemd command is so cool 
https://www.freedesktop.org/software/systemd/man/latest/systemd-soft-reboot.service.html
Finally a clean way to rapidly re-start everything other than the #Linux kernel… for me, it is extremely useful to be able to do that after applying desktop & graphics stack updates, and to be able to log back in within 10 seconds.
Throwing the idea out here: it would be very nice if someone figured out a way to write a #GNOMEShell extension to provide "Soft reboot" as an alternative to cold reboot!