Of all the types of spam emails, the ones I find the most annoying are the self-referential ones. These emails start off with a fairly pathetic plea, such as “We’ve been trying to contact you for weeks but you won’t do us the courtesy of replying”. Then, they include a forwarded copy of each message they supposedly sent before. Maybe they’re trying to take advantage of some sort of reciprocity principle, but the tone comes across as arrogant and accusatory. Since very few people will remember getting the prior messages in the spam chain, let alone feel guilty about ignoring them, I think this is a particularly ineffective way to peddle products. After all, simply pretending you have a business relationship with somebody doesn’t automatically make it real.