This is a fantastic infographic about the psychology of influence. A lot (if not all) of these are talked about in-depth in Robert Cialdini's book Influence: The Psychology of Persuasion, but it's a great visual primer of some of the psychological tactics that businesses use to sell you stuff.
Let me know what you think about this one.
Photo by John DeFazio (Own work) [CC-BY-SA-3.0], via Wikimedia Commons
Infographic by Pardot