Counters aren't usable

I'm not 100% positive but if I had to guess, I would think it has to do with the footprints of the objects, every object has a footprint meaning the sims can't go thru that square, so even if you aren't snapping deco items to a slot that footprint is still there and covering up that counter tile making it unusable, it's the green square you see when placing items.

The only way to fix this would be to remove the footprints, which is fine for things that are sitting on a surface area (counter, table, shelf, etc), but by removing the footprint for things that would typically be placed on the floor ... sims would walk right through it because essentially there's no bounding box around the items to make them route around it. They'd just walk through it and then you'd have half the sims community up in arms about sims walking through objects and how immersion breaking it is.

Plus for some reason, EA thought it was a great idea to limit certain items to certain slots. So they the slots on surfaces are categorized as small, medium and large deco slots, meaning if an item is tagged as a large deco item, it will only snap to a large deco slot, even if visually the item is small and should theoretically fit on a shelf, if it is tagged as a medium or large deco item it will not fit on shelves, because shelves only have small deco slots.