I did not say mental blunders can not be proved to have cost a game, but I am saying no one on talksox has been able or willing to do it. At the same time, any of us can cite specific examples of when weak hitting or poor pitching cost us multiple losses. My gosh, our hitting has been so bad MLB is about to nail us for electronic stealing of signs, which Is cheating. You want bad baseball to get mad about, try that on for size. It is ignominious.
As for JBJ and maybe Leon's inattention on the base paths last night, I not only don't care because it had no effect on the game, I also don't consider it a good example of bad fundamentals because it was such an unusual situation. I and others had trouble realizing that, even with Leon out at home JBJ could still be a force out at 3b. On a pop fly to left field yet. A natural instinct on a very catchable pop fly to LF is to stay put because you can't advance from 2d base when it is caught. That's also why Leon was so slow to react and out by a mile at home.
And, while we're on this topic, lets not forget that pop fly was getting close to infield fly rule territory. The infield fly rule was adopted by MLB to eliminate easy double play force outs created by clever infielders who purposefully dropped popups with runners on 1st and 2d and one or no outs. They wisely recognized the advantage gained by intentionally dropping a popup to get a double play instead of just one easy out.