I store my drinking glasses upside down and this is not because of dust as they are in a closed cupboard, but in case there are cockroaches!
Or indeed any other animals -probably started when I lived in the country on 5 acres and there were a lot of mosquitoes and "things" about there.
Right side up, because the ones we use every day are in use too much to gather much in the way of dust, and with those we seldom use like champagne flutes I don't mind giving them a quick wash before using them.
I store my drinking glasses upside down.....dust stays out and if I haven't dried them properly (but OFCOURSE I always do.....) any little trickles of water don't remain. For folk who may have a resident mouse running around....this keeps mice errr...bits...from getting in too!
I used to store them upside down until I read the result of research that it was more hygenic upside up. The study argued that there would be more contamination on the top of glass by having it upside down with the part that touches our mouth touching the shelf. Insects that crawl on the rim of a glass when upside up are likely to fall in, becoming trapped and make it obvious glass is not clean. I have often wondered how dirty their shelves must have been in that study.
I still store mine up, just in case.
Mine are stored upside down for the same reason as Finy. My flutes and wine glasses hang upside down in a special fitting screwed to the top part of the bar hutch and are used a lot but do get a bath now and then just because I've so many they can't all be used.