You're probably familiar with the sometimes misinterpreted idea that short term memory is limited to seven (plus or minus two) pieces of independent information. My personal corollary is that I can remember only three (plus or minus one) interesting things about anything. This phenomenon is disturbingly scale-independent: I can remember only three things each about my childhood, World War I and what I ate for breakfast this morning.
I spent five years studying psychology. Here are the three interesting things I remember:
1. The Fundamental Attribution Error. We tend to explain the behavior (especially bad behavior) of others by the kind of person they are ("Ashlee Simpson is a fake") and our own behavior by the particular circumstances ("My drummer hit the wrong button and/or I had acid reflux.") I recognize this error everyday in myself, in respondents, in the news. In fact, any randomly selected newspaper front page can be usefully interpreted as a series of proofs and variations on the Fundamental Attribution Error.
2. The mesmerizing power of irregular reinforcement schedules. I was reminded of this by the ad above for a bank account tie-in with the Dutch lottery. Every month you have the chance to double your balance and enter the Lotto drawing. For this, you accept a lower interest rate which, as the website cheerfully points out, might be less than you would spend on an equal number of Lotto tickets! Isn't there something brand discordant about a savings bank/lottery relationship? Aren't savings banks the champions of regular reinforcement? And why does regular reinforcement seem morally superior to irregular?
3. Everybody is interesting. Our minds are too complex not to throw off an ongoing shower of unexpected, incomplete, meaningful stuff that's worth thinking about. If someone seems boring or shallow, it's because you and s/he are not in the right situation or relationship to one another. Change the situation. Ask a different question.