Janitors, cooking staff, security, sysadmins. Making friends in those groups will make your life so much easier. As a sysadmin myself, I'll go out of my way to help someone I like, and/or is grateful for my work.

The people that keep the bathrooms useable are pillars of civilization.

The janitor never makes huge reorganizational changes with 300 layoffs then calls it an "efficiency package"

being a janitor require more qualification than being a CEO