Title: A Major Lifelong Taboo You Must Never Commit! Our Ancestors Were Too Accurate in Judging People: These Five Types of Individuals, You Must Never Befriend Deeply!

In the complex web of human interactions, the ability to discern character is paramount. Our time, energy, and emotions are precious resources. Investing them in the wrong people can, at best, drain us and, at worst, invite disaster. Ancient wisdom has long distilled principles for judging character. This article provides an in-depth analysis of five personality types from whom you should firmly maintain distance, helping you purify your social circle, protect your personal energy, and move towards a clearer, more prosperous life.

I. The Mercenary and Calculating: Opportunists Prioritizing Gain
These individuals completely instrumentalize relationships. Their closeness depends solely on your current "usefulness."

1. Core Traits: Eyes only for power and money, lacking genuine affection or principles. Skilled at swaying with the wind and currying favor with the powerful.

2. Behavioral Patterns: Flock to you when you're successful, full of flattery; become cold and distant, or even kick you when you're down, during hardship.

3. Potential Harm: Highly likely to betray friends or partners at critical moments for personal gain, placing promises and camaraderie beneath the scale of profit.

4. Coping Strategy: Maintain polite yet clear boundaries. Never befriend deeply, and certainly never entrust them with important matters or secrets. As the ancients said, "Friendships based on power and profit are difficult to sustain long-term."

II. The Hypocritical and Cunning: Deceivers with a Discrepancy Between Appearance and Reality
They excel at using words and performance to create a false friendliness, while their hearts are full of calculation, making them among the most insidious dangers in social interactions.

1. Core Traits: Duplicitous, words and actions contradict. Say one thing, do another. Proficient at reading people and emotional manipulation.

2. Behavioral Patterns: Warm and sincere to your face, but spread rumors and sow discord behind your back. Their aims are often to extract information, resources, or achieve ulterior motives.

3. Potential Harm: Consumes your trust, disrupts your judgment, placing you in a complex whirlpool of gossip and strife without your knowledge.

4. Coping Strategy: Adhere to "listen to their words, observe their actions." Judge by observing the consistency between their promises and actions over time. Be wary of excessively sweet words.

III. The Untrustworthy and Unvirtuous: Sources of Danger Lacking a Bottom Line
Trustworthiness is the foundation of establishing oneself; virtue is the cornerstone of navigating the world. Those lacking both are unpredictable and highly destructive.

1. Core Traits: "Untrustworthy" means making promises lightly and breaking them often, treating commitments as trivial. "Unvirtuous" means improper conduct, lacking basic moral restraint.

2. Behavioral Patterns: Habitually break promises, willing to harm others for self-benefit, may lie, spread falsehoods, or backstab.

3. Potential Harm: Directly leads to failed cooperation, damaged reputation, and may even entangle you in legal or ethical risks.

4. Coping Strategy: Once identified, distance yourself immediately. Do not attempt to reform them or take chances on cooperation. "Near vermilion, one gets stained red; near ink, one gets stained black." The best way to protect yourself is to stay away from the source of contamination.

IV. The Stubborn and Opinionated: Emotional Black Holes Resistant to Growth
They are not necessarily bad people, but their closed-mindedness and refusal to communicate make any constructive relationship exceedingly difficult.

1. Core Traits: Inflexible thinking, viewing their own opinions as absolute truth, unable to accept any differing views or new information.

2. Behavioral Patterns: Eager to refute others in any discussion, never admit mistakes even when wrong, skilled at making excuses to defend themselves.

3. Potential Harm: Interacting with them leads to endless, fruitless arguments, greatly consuming emotional energy and hindering mutual progress.

4. Coping Strategy: Reduce futile arguments. On non-principle matters, show respect but hold your own views. Reserve energy for those willing to engage in two-way communication and grow together.

V. The Ignorant and Unwilling to Learn: Energy Drains of Passivity and Negativity
Here, "ignorant" primarily refers to a mindset of complacency and refusal to learn, not low intelligence. They can subtly lower your state of being.

1. Core Traits: Unwilling to think, refuse to learn, habitually complain rather than solve problems. Often accompanied by unwarranted stubbornness.

2. Behavioral Patterns: Spread negative talk, resist new ideas and methods, interfere with others' judgment and decisions based on their narrow understanding.

3. Potential Harm: Their negative energy is contagious. Long-term association can dampen your ambition and slow your growth.

4. Coping Strategy: After encouragement proves ineffective, decisively maintain distance. Actively approach good friends who are "open-minded, eager to learn, and willing to think through problems," nourishing each other and advancing together.