Josh has a good post on the no-nut minhag on RH. As my father is fond of saying, I believe in the name of the Klausenberger, we would do well to remember that chet also has the same gematria as chet. This flies in the face of the old 'you are what you eat' theory. REfraining from nuts seems a bit, well, nuts, and eating them seems perfectly sane.
In a similar vein, I try, when possible, to daven 'ke-vatikin' on RH, so that the Rebbetzin can go to shul for tekiot and mussaf. Inevitably, it means that I would nap at some point in the afternoon. Aha! But that will mean that my mazal will sleep this year, or that I'll have a sleepy year, or whatever.
Since when did this old wives tale become more important than the old wives themselves?