The one I've been repeating to myself over the past several years of SMing at an opera company which has a total of 3 onstage rehearsals before opening (one 4-hour tech, one 3- to 3.5-hour orchestra rehearsal, one 3-hour final dress):
"The show will open on Saturday."
And at the end of the opening night show, it's usually "Well, that was a great final dress for me."
Not really advice, but as others have said, it's not really life-or-death at most points, so time will march on and we'll make the mistakes we make.