If you want to impress someone (whether in an interview or presentation), avoid airing your entire laundry list of achievements. Otherwise, you might fall victim to the "Presenter's Paradox."
Discovered through a series of studies, the phenomenon occurs when "mildly favorable information dilutes the impact of highly favorable information" in the eyes of the perceiver (your potential new boss or client).
Essentially, more is not better if what you present seems to have less quality than your other offerings, the Harvard Business Review recently reported. The research showed that the perceiver will evaluate what is presented as a whole, rather than focus on each individual part. So, for example, if you're pitching a VC and you list 10 reasons your management team is the best in the industry--the 3 least impressive reasons will have the most influence on the overall message.
"We all face the important task of deciding what information to include in our presentations," one researcher said. "However, the present analysis suggests that we often inadvertently dilute the very message we seek to convey simply by our efforts to strengthen it."
This concept can be applied not just to an individual's presentation, but how you present a product as well.
In one study, 54 participants had to chose between two iPod Touch packages. One contained an iPod, cover, and a free song download. Another had just an iPod and cover. Participants were willing to pay an average of $177 for the first package and $242 for the second. HBR noted the low-value free song download cheapened the iPod package by a whopping $65.