The feeling of the brain being actively engaged with too many thoughts, to properly address any new issue, never mind any of the existing issues, is a common feeling – for me anyway.
Once you have several mental balls in the air that are connected to some strategy to get something delivered productively, it’s impossible to pick up a new one without letting drop at least one. [The other metaphor is the plate-spinning circus act.]
In correspondence today Richard Emerson coined the expression:
Mental Switching Costs
As well as reflecting the existing thought process above, that formulation instantly suggested its relationship to the (Friston) Free Energy Principle and all those systems-thinking consequences of Markov-blankets and active inference for living and sentient organisms. It’s all about efficient and effective use of resources, and when one of those costly resources is conscious attention itself, maximising which tasks can be left to the sub-conscious.
Isn’t it great when a plan comes together?