Most of the time, if you ask someone about their agenda, it turns out that it involves doing what's on someone else's agenda.
I need to do this for my boss, this for my husband, that for the PTSA and this other thing for the kids. As soon as you turn over your agenda to others, you're giving up one of the biggest opportunities you have to contribute. Setting an agenda is often as important as checking the boxes.
Obviously, you can't be part of any system without engaging with other people and their agendas.
But perhaps we've absorbed that habit so completely that we've ceded all responsibility and in fact don't even have an agenda any longer...