The phenomenon you describe can be attributed to several factors, and understanding these reasons can help shed light on human behavior:
Impression Management: Initially, people may put forth their best behavior to create a positive impression. This can be driven by social norms, a desire to be liked, or the need to fit into a new group. They might be trying to gain trust and acceptance before revealing their true selves.
Self-Presentation and Social Acceptance: People often fear rejection or judgment, so they may act friendly and accommodating at first to be accepted by others. Once they feel secure in the relationship or group, they may become more comfortable expressing their true feelings and attitudes.
Hidden Motives: Some individuals may have hidden motives, such as wanting to gain something from others or using their kindness as a means of manipulation. When they achieve their objectives or feel they no longer need to maintain the facade, their true intentions come to the surface.
Testing Boundaries: In the early stages of a relationship, individuals might test the boundaries to see how much they can get away with. They may gradually reveal their true nature to gauge the reactions and tolerance levels of others.
Long-term Stress and Pressure: External factors such as stress, pressure, or personal challenges can affect someone's behavior over time. When individuals are going through difficult periods, they might become more irritable, withdrawn, or self-focused, revealing their less friendly side.
Comfort Zones and Familiarity: As people become more comfortable with others, they may let their guard down and show their true colors. This is because they no longer feel the need to maintain the initial friendliness and politeness.
Mismatched Expectations: In some cases, initial friendliness might create unrealistic expectations. When others fail to live up to those expectations, it can lead to disappointment and the perception of mean or selfish behavior.
Personality Traits and Dispositions: Some individuals naturally have agreeable and friendly personalities, while others might have less empathetic or altruistic traits. Over time, these inherent personality traits may become more evident.
Limited Perspectives: At first, people might only see a person's pleasant side due to limited interactions or biased observations. As they spend more time with someone, they gain a fuller picture of their behavior, which may include less desirable aspects.
It's important to note that not everyone follows this pattern, and there are many genuinely kind and friendly people who maintain their positive behavior consistently. Additionally, people can change over time, and what might seem like their "true colors" at a specific point in life may not define them forever. As we interact with others, it's crucial to remain observant, set healthy boundaries, and communicate openly to foster genuine and healthy relationships.