Bowls right side up, because they stack better. Glasses upside down, because they stack better and don't topple over

Both right side up at my place.

I always found it kinda weird to have the drinking surface of the cup touching the bottom of the cabinet.

I always thought the glasses down was because they were not always dry at the bottom and couldn't towel them out--and if you tipped them over they would drain. Bowls can be towel dried just fine.

Location-dependent. In humid states, right-side-up glasses will frequently retain their moisture long enough to begin to mold while upside-down glasses drain out and dry more quickly. In dry states, it really doesn't matter and right-side up vs upside-down is either a matter of personal preference or physics. Our glasses are more or less straight-sided, so their stability is no greater upside-down than right-side-up.

If I didn't have a dish washer I'd probably end up putting them face down. I usually start it up before I head off to work, so all of the water has drained out of the glasses by the time someone gets home.

Putting a glass in upside-down leaves moisture trapped within the glass, as it has no place to escape to aside from soaking into the wood of your cabinet. A glass that's placed in the cupboard right-side-up still doesn't allow water to escape, unless you habitually neglect to close your cupboard. This is why, prior to dishwashers with a drying cycle, we used to have those racks to put your dishes in, with the mat underneath that drains the water into your sink. You do not put away your dishes and glasses until they are dry.

The correct answer is slugs. In certain geographic regions, leaving your glasses and bowls right-side-up in the cupboard is a good way to find a slug in your glass the next morning when you want a drink of water.

we used to have those racks to put your dishes in, with the mat underneath that drains the water into your sink. You do not put away your dishes and glasses until they are dry.

Putting a glass in upside-down leaves moisture trapped within the glass, as it has no place to escape to aside from soaking into the wood of your cabinet. A glass that's placed in the cupboard right-side-up still doesn't allow water to escape, unless you habitually neglect to close your cupboard. This is why, prior to dishwashers with a drying cycle, we used to have those racks to put your dishes in, with the mat underneath that drains the water into your sink. You do not put away your dishes and glasses until they are dry.

The correct answer is slugs. In certain geographic regions, leaving your glasses and bowls right-side-up in the cupboard is a good way to find a slug in your glass the next morning when you want a drink of water.