When you open a fresh jar of peanut butter do you only work through one side until it is completely empty then start on the other side?
Or when you get those shallow tubs of hummus does it have to make it back home undisturbed? Then one of the baggers at the grocery store shoves it sideways into the bag completely ruining the symmetry.
Absolutely no digging in to the tub of butter, and no other food bits (usually bread crumbs) must be left inside.
If dug in to, it must be smoothed out before putting back in to the fridge. As for the crumbs, take them out and put them back on to the bread they came from. Now the butter can be put back in to the fridge.