Trends and consumer tastes can alter how in-demand your product is and whether your demand curve will shift. This can especially be the case around the holidays, when a popular, "it" toy may become the thing to buy. For example, one year a motorized gerbil may be the must-have Christmas toy, causing the company that produces these motorized gerbils to see a huge spike in sales and demand. The following year, though, motorized gerbils may be passe, and the new trendy toy may be a mechanical puppy. Changes in consumer tastes and trends can affect how high demand will be for a product, thus causing the curve to shift in either direction.