DislikedI do not completely agree with you on this. Statistics is obviously important but trading is more of an art than mere drab statistics.
I can see it from my own trading. My bad months actually results because of psychological issues not because whatever I am doing is not working. For example, November I moved stop on my short GBP/JPY trade and moved significantly. Lost 3 time as much as I originally risked. That was the only trade in a year that I behaved this way. I was not taking profits on another profitably trades and lost some more trades. So,...Ignored
Concerning trading being an art I completely agree, but even discretionary trading you can quantify in terms of profits and losses, thus you can and should do statistics. Otherwise there is no point whatsoever of keeping a journal.
Statistics just show reality, and not doing statistics will dillute yourself into believing you have a working system when in fact you might not have one.
We probably will never agree on that point, but for me statistics is everything and not doing a statistical analysis of your trades is foolish in my eyes. And again, any kind of trading can be quantified, it is only more complicated to quantifiy discretionary systems, since you have to do everything manually.