As a German I have a reflex to wanting to open the windows in most indoor situations regularly, when I am in AC'ed/ventilated situations. Of course in my AC'ed office, the windows wouldn't open, but surely the air does not feel 'fresh' enough.

Pretty sure when returning to the office post-covid we'll see some discussion on Meeting room CO2 levels. I occasionally had a hard time keeping my eyes open in crowded meeting rooms which never happens even in the most boring meetings that I have remotely.