I believe that suitcases don't belong on beds. Also shoes, and street clothes.
It's a lesson learned from my grandmother, who also taught that plates go on top of placemats, condiments should be decanted into dishes with spoons before going on the table, and the hotel room should never be near the elevator or the ice machine.
I realize these little quirks might make me fussy in someone else's eyes, and if you put me under oath I'd have to confess that my grandmother was a touch fussy. But she was also grand.
At her funeral I spoke about my grandmother's influence on my life and I said that she "taught me that I should ask for what I want. and she taught me what I should want."
Please, don't put your lipstick on at the table.