Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: Terrible option for makeshift shelves

Initially, these shelves seemed to work fine... and then we started actually using them. First, the plastic mounting guides are very flimsy. When weight is on the shelves, they routinely warp and, coupled with the movement of the door they're attached to, the shelves come out of the bottom mounting holes on a weekly basis. The worst part about these shelves though is the lack of a side bar. When mounted to a door which is their intent, the momentum of the swing pulls items outwards towards the side... but the side only has one bar at the maximum height so when it holds tall items that fall over due to the door swinging or items that are shorter than the shelf, they come flying out the side. Usually this is a can of cooking spray or a short can of diced tomatoes which are both heavy enough to leave an awesome bruise on mytoe after opening the door in a hurry while fixing breakfast... nothing like limping into work because you busted your toe on a can of Pam.