Geometric mean returns and portfolio choice

I've been reading Michaud's "A Practical Framework for Portfolio Choice" about once a quarter for a while now to see if I can identify dumb mistakes that I continue to make here.  Evidently my reading is not sinking in because every time I re-read this I realize or re-realize some of the errors I keep making.  I also look for things in the link where I do not understand something all that well (and probably should) to come up with areas to explore in the future.  So far, over a couple years, I have not come away short of things to brush up on.  Michaud is not Moses with stone tablets, of course, and there are other points of view, but I have to say that there is a lot of fun stuff in there.  I doubt I would be making any serious errors by continuing to beat some of this stuff into my head.