Hillary - I completely agree that having kids makes things more complicated
Also agree that less "stuff" makes life easier.
My main secret simplicity is lots of plastic tubs, lol. My 4 yo has clear plastic bins in her room for all her stuff to go into. Each one is marked with its intended contents (whether that's what happens to be in there at the moment or not). Worse case scenario, we can toss all our stuff into the bins, stick the bins of their shelves and the world looks cleaner.
On the emotional side - letting go of anything I have no control over makes life easier and happier. Oh, and refusing to get involved in drama...