Make CallToThread more deterministic, picking the least loaded thread; fix up some sleeps; create a SingleTaskDaemon which performs only one task at a time
Fix some focus issues, use SingleTaskDaemon instead of a "lag timer", remove some ununsed code, put __init__ at the top of a class, the usual stuff
Hide exception traceback on shutdown (whoops)
Remove some sleeps (replace with waits); tidy a bit; add a superclass of DAEMONWorker intended for subclassing with access to self._event_wait
More sleep tidies

Remove a sleep.
Annotate "necessary" sleeps so that you know what they are when grep
sees them.
Remove a Pokémon exception handler.
Remove what looks like a hypercorrect use of os.linesep
Join threads instead of sleeping until a variable changes
Make both DBs join instead of sleeping (& refactor) tighten an exception handler & remove print
What do you have against dict literals?
Plop in another mixin to mop up some dupes