The most significant indicator of people’s character comes through their actions over time. Despite what people say about the lessons they have learned (see Howard Hughes), and how they have changed over the years, you will inevitably notice the same actions and decisions repeating in the course of their life. In these decisions they reveal their character. You must take notice of any salient forms of behavior—disappearing when there is too much stress, not completing an important piece of work, turning suddenly belligerent when challenged, or, conversely, suddenly rising to the occasion when given responsibility. With this fixed in your mind, you do some research into their past. You look at other actions you have observed that fit into this pattern, now in retrospect. You pay close attention to what they do in the present. You see their actions not as isolated incidents but as parts of a compulsive pattern. If you ignore the pattern it is your own fault.

You can discover what your enemy fears most by observing the means he uses to frighten you.

Introspect daily, detect diligently, negate ruthlessly.

Those who look for the bad in people will surely find it.

One should attend to one's enemies, for they are the first persons to detect one's errors.

If you want to know what a man is really like, take notice of how he acts when he loses money.

Don't just listen to what the person says; watch what they do. Because what people say is one thing, but what they do reveals the truth about them.

If you look for the bad in people expecting to find it, you surely will.

Pay attention to your enemies, for they are the first to discover your mistakes.

See a person's means (of getting things). Observe his motives. Examine that in which he rests. How can a person conceal his character?

You can only find out what you actually believe (rather than what you think you believe) by watching how you act.

Everybody has that thing where they need to look one way but they come out looking another way and that's what people observe. You see someone on the street and essentially what you notice about them is the flaw.

The idea of: watch what people do not what they (or their staffers) say.

Watch people do their most common actions; these are indeed the things that will tell you the real character of a great person.