By now, you already know the concept of classical conditioning. But I'm going to tell it to you anyways. An unconditioned stimulus (US) causes and unconditioned response (UCR). By associating a conditioned stimulus (CS) with a (US), one can achieve a conditioned response (CR).
Most of us probably see this as a very simple concept that would only work to teach less intelligent species. This works with dogs (think Pavlov), other animals, and babies (think Baby Albert and his fear of white rats). Most people probably believe that they are "too smart" to fall for this or not to recognize when they are being classically conditioned.
However, classical conditioning is all around us; in advertisements, especially. Because of higher-order conditioning, companies can make us feel a certain way towards their product by associating it with something else.
This commercial advertises for Old Spice. It uses approval of attractive women as a conditioned stimulus in order to make the consumer want to buy their product. Although most of us don't think about how advertisements try to condition, consumers are affected daily.
Humans can apparently be classically conditioned on lower levels too. In this video from the office, Jim classically conditions his co-worker, Dwight.
Sorry for the bad video quality. I'm on a horse.