I'm mystified by your mystification! What's unclear about it? Is it the distinction between the "up" and "down" sides of a slice of bread?
Here's a visual aid:
What do you do if you buy square bread? Yeah, I was thinking top and bottom referred to the sides of the bread in which case I wouldn't know which was which. It would be like trying to eat a sandwich in outerspace just floating and twirling gently with no sense of up or down.
The first man to raise a fist is the man who's run out of ideas. H.G. WELLS
The first principle is that you must not fool yourself, and you are the easiest person to fool. FEYNMAN If this is monkey pee, you're on your own.SCULLY
I am particular about the order in which applications appear in my task bar on my computer. If I accidentally close one, I am often tempted to close everything and start again so they are in my preferred order.