The Baked Goods Theory of Social Interaction

This is a pretty good rule of thumb. I had never thought of it explicitly like that.

I also have had some success with an 'office hours' type approach. I let everyone in my social group know I'm available for a drop in or call from 5 to 8 on Thursdays and it helps reduce the friction.

The less active planning required, the more likely it is to happen.