It always started out okay. Put one corner of the sheet on one corner of the bed. However, he would then attempt to put the other corner of the same side of the sheet onto the corresponding corner.
“No, that’s not right,” I would (once again, with feigned patience) explain. “You MUST put the corner that is directly diagonal to the original corner onto the mattress next.”
Invariably, he would ask why. The answer: Because. That’s the way my mom did it.
I never really bothered to ask Mom why she did it that way. I always presumed that it was because the sheet would somehow fit tighter onto the mattress if done that way. Perhaps sheets weren’t made as well back then. It doesn’t matter why. I just know it was the right way to do it because my mom did it that way.

I asked my sisters if there were things they do simply because Mom did it that way. Yes, laughs one sister. Mom always properly set the table, so no matter where she and her husband eat (even if it’s off of the coffee table in front of the television), she sets the plate, carefully folds the napkin to the left, and properly places the flatware, fork to the left, knife to the right.
Of course, says the other sister. She cannot (not will not – CANNOT) throw away a little bouillon cube jar. They can, really MUST, be used for such things as leftover salad dressing, buttons, or garlic butter.
Mom’s influence goes to all of our cooking habits as well. Mom used garlic salt every time she browned ground beef. So do we. Mom took the lid off of the potatoes she was boiling to ultimately mash and let the water evaporate, which she said concentrated the flavor into the potatoes. So do we. (Well, I must admit I just learned this habit of Mom’s recently from my sister, but it is undoubtedly the way I will boil potatoes from this point forward.)
I have a friend who used to cut off a corner of her ham every time she cooked one for Easter dinner. One day, she told me, her mom was at her house for dinner. Her mother watched as she dutifully cut off the corner of the ham and tossed it aside to use in soup. “Why did you do that?” her mother asked. Surprised, my friend said, “I did it because you always did that when you made ham.” Her mother laughed, and responded, “I did that because my pan was too small to hold a whole big ham!”
I would love to hear what sorts of things others do for no other reason than that is what their mom or dad did.