If you want to learn about someone (we will call him the target,) don’t waste your time asking that person anything about himself. You will never get the whole story. This person may guard information, not tell whole truths, be biased, or simply give you the run around. The two people who will give you the best information on your target is your target’s best friend and his worst enemy. There are a number of reasons for this, but, generally speaking, friends are less likely to remember what bits of information are “confidential” or if they are common knowledge. People are unlikely to keep someone else’s secrets as well as that person would. On top of that, they are less likely to be concerned about how you intend to use that information than your target would be. For this source of information, there are lower stakes in the conversation, which means they are less likely to lie or deceive, ultimately giving you a higher quality of intelligence.