Find an example, or make up an example, of an interaction term in a model (this can be from the world of marketing, or from anywhere else). A very good answer to the last part of this question will include some genuine reaction from you -- finding an example of an interaction effect is only a half-credit answer here. In a 3-5 sentence paragraph describe what you found (or invented). What are the variables that make up this interaction? Is the effect of their interaction on the outcome positive, or negative? How do you feel about the interaction? Does it make sense to you? Or does it surprise you?