What if *that* were up?

When I was little, I used to make my dad dangle me upside-down and carry me around the house.  It was one of my favorite things because when he did that, I didn't have the experience of being upside-down.  I simply had the experience of the ceiling being "down."  I imagined I was walking on the ceiling, navigating around light fixtures, stepping over the inexplicable foot-high walls that separated every room.

For years, I have sat--in calculus class, in dining rooms, on busses--and tried to imagine what would happen if gravity suddenly changed directions.  I'd imagine everything falling to the new down, try to estimate how badly I might be injured in the fall, look for handholds to grab on to, and plan how I might venture in the new sideways world.  Because it would be like adventuring in a new world, wouldn't it?  You probably wouldn't be able to leave the building you were in when it happened; at least, not without a ladder, which could help get to the neighbor's house.  A house across the street would now be on the other side of a deep chasm.  Billions would be dead or dying.  Do you ever make plans for the zombie apocalypse?  Yeah, me too.  But I also make plans for the gravity shift apocalypse.

Think about it.  Think about all the places you can walk now that would be utterly inaccessible in the sideways world.

Upside-down would be even worse, of course.  Particularly if you were outside.  Sometimes I lie in the grass and look up at the sky, and I make the sky "down."  I am stuck to this grass ceiling, perhaps by some upside-down-world static electricity, dangling over an endless fall.  Could I grab that telephone line on the way?  Would it support my sudden weight?  Would there be any survival strategy if I wound up clinging to a power line?  What does "grounded" mean now?

Attempts to survive a straight-up gravity reversal from outside would be futile, so I normally don't bother.  I just cling to the ceiling and look down at the sky, and enjoy the feeling.

Usually I assume other people think more or less like I do, but I've yet to meet anyone who shared these considerations.