i thought about this sort of thing a lot because we ran a "comfort zone expansion" class as part of CFAR workshops. eventually came to the conclusion that the object-level comfort zone (activities) was way less important than the meta-level comfort zone (internal states)
Nice - I guess in that frame what I'm thinking is when you end up with "pushing up against the edges fo your comfort zone" outside your meta-comfort zone, your object-comfort zone might actually shrink (gradually but potentially continually)