I went without shampoo for two months because of this. Not my preferred means of hair care. I thought I was buying a twopack of shampoo off of Amazon. I actually bought a combined shampoo+conditioner package. The brand labeling was so prominent I didn’t even notice. So instead of applying shampoo+conditioner, I was doing conditioner+a different conditioner. And it wasn’t soo bad that it was immediately obvious. But yeah, I’ve fallen victim to this.