Concentration

I heard that playing chess is good for your concentration.  Lately, I've been discovering that not only is the converse of that statement true (concentration is good for chess) but more importantly, the inverse of the converse is true (lack of concentration is bad for chess).

Sometimes I find myself repeating the words of Pooh, as he fell from the honey tree:  "If only I hadn't -- ", "You  see,  what  I  meant  to do --"

Now where's that "Undo" button...