My friend and I have commandeered the salad drawer in the communal fridge as no one else seems to think of using it, and it means our food is safely hidden away from lunch thieves and fridge rulers.
We have someone who uses everyone else condiments and puts the empty jars/ bottles back in the fridge. We also have someone who brings rice to work most days, still hot as they've cooked it that morning (?!) leaves it on the side in a sealed Tupperware so it's all condensationy (swarming with bacteria) doesn't come and eat it at lunch time so it stays on the side for a few more days until it suddenly disappears!
People are so weird about food. Never once have I looked in the communal fridge and thought "oh that food that I didn't bring in and someone else will be looking forward to eating looks good, I'll have that" but people's food does get eaten on occasion.