What Sue Deppe didn't mention in her message is that she and Steve have been thoroughly involved in the design and building of a new house right on the lake, looking at beautiful mountains. Talk about sources of affect other than Behavior OnLine!!! Glad to have you back, Sue, especially after you've just completed your new nest.
And what an important subject you choose here. In the language established by Tomkins within script theory, much of your post would be described as matters of "nesting." The threshold from which any sequence of stimulus increase, stimulus decrease, or stimulus level is initiated will determine a great deal about the eventual stimulus-affect-response sequence that we will see as a scene.
Additionally, Tomkins noted fever, hunger, and fatigue as conditions that lowered the baseline for negative affect.
I'm fascinated by your report that a pre-dinner walk is less satisfying than a post-dinner perambulation. I equate a walk before dinner with a glass of beer or wine. When I get home from my usual 11-hour day I need to chill out. I'll even watch an episode of the A-Team (ugh) when the day has done me in too much. But a mile or so walk is the perfect amount of exercise to put me in a better mood. When Roz and I walk after dinner, I end up tired, cranky, and unable to work at my desk before bedtime.
The important thing, as you stress, is to plan for success. We've got to learn our own bodies, our own predilection for any affective experience. If we get really good at it we may be able to help other people.