I'm always intrigued by the different ways we do things and trying to figure out the reason why. If there is one!
What set me off on a train of this thought was 'unstacking' the dishwasher. See, I was replacing glasses in the kitchen cupboard, and setting them rim upwards. My observation is that plenty people set glasses, mugs, cups and so forth rim downwards. Does this originate from open shelves, when you didn't want dust or insects to settle inside, I wonder? Isn't it better now that we have doors to our cupbards, and won't they last longer if you set them rim upwards?
And then there's the business of putting cutlery inside the dishwasher, or into the dish drainer for that matter. Most people I think put the handles downwards. I tend to mix it up, here, so as not to spike myself. So, the tines of the forks go downwards and the blades of the knives too.
Now that I've set you all topsy-turvy, I'll get back to my writing. :-)