Worst ineffective cosmetics

It is a Migu Hara product called the Acne Control Serum. It has a scent similar to a menthol patch with a slightly stinging sensation. They claim it is good for oily and sensitive skin, but putting all that aside, it has absolutely no effect. It is not exactly a cheap serum, so who would use it if it doesn't work? It has a gel-like texture with a non-sticky, hydrating feel, but the application is poor as well.