Amen, Puppy.
I'm getting annoyed with jumpseater behavior here. Bottom line is, ASK before you do anything other than take a whiz in the lav.
Want fire up your laptop or make a bed out of the seat cushions? Ask. Want to eat? Ask the FE or front seat occupants what is available for chow. Where to put your bags, in the belly or topside? Ask. Want that delicious Diet Coke that's sitting all by itself? Ask.