For me, using Facebook cookies in the same browser as work stuff blows my mind. I specifically write in the onboarding of my employees “Create a separate Chrome or FF profile to use your Facebook and other personal browsing”, and only half respect this rule, interns being specifically bad (experience workers do want work/home isolation). They receive quite a scolding when I catch them, but the damage is done: All websites have immediately registered who they are associated with, who their colleagues are, etc.

Stringent security rules and obnoxious firewalls exist because people don’t respect cool rules.