For me, festival affinity is a part of my sims' personalities. Some of them never miss Humor and Hijinks, some of them (especially the Hot-Headed ones) wouldn't be caught dead at Humor and Hijinks. What I would love is if there was a menu you could open up under household (phone or computer) where you could select which festival popups are turned off for that household and which are turned on. So, if none of the household members care about the Festival of Light, I never hear about that festival when I'm playing that household. The weekly notification of Ravenwood events that we currently get could be one selectable notification, as well as a weekly notification of Ohanali Town events (which we currently don't get, but I would really like).
I'd also like an option in the phone social menu where you can indicate if an individual is available to accompany friends to specific events. This would manage whether they get phone invitations, and which events they can be invited to.