1. The Dunning-Kruger effect: This psychological phenomenon refers to the tendency of incompetent individuals to overestimate their abilities. People with low ability or knowledge in a particular domain often mistakenly believe they are much more skilled or knowledgeable than they actually are. Conversely, highly competent individuals may underestimate their abilities, assuming that others are equally capable.
2. The mere-exposure effect: This effect suggests that people tend to develop a preference for things or individuals they are exposed to frequently. Familiarity breeds liking, even if there is no inherent quality or attractiveness in the object or person. This phenomenon has implications in advertising, as repeated exposure to a product or brand can increase positive feelings towards it.
3. The placebo effect: This phenomenon occurs when a person experiences a perceived improvement in their condition or symptoms after receiving a treatment that has no therapeutic effect. Placebos can be in the form of sugar pills or even sham surgeries. The placebo effect highlights the significant role that a person’s beliefs, expectations, and psychological factors can play in influencing their physical well-being.
4. The paradox of choice: Having too many options can lead to decision-making difficulties and decreased satisfaction with the chosen outcome. While having choices is generally considered positive, research has shown that an excessive number of options can lead to increased anxiety, indecision, and dissatisfaction. People may feel overwhelmed by the abundance of choices, fearing they will make the wrong decision.
5. The bystander effect: This social psychological phenomenon occurs when individuals are less likely to help a person in need when others are present. The presence of other people creates a diffusion of responsibility, where individuals assume someone else will take action. As a result, each person feels less personally responsible and is less likely to provide assistance. This effect emphasizes the importance of individual intervention and taking personal responsibility in emergency situations.

These odd but true facts about psychology shed light on the complexities of human behavior and the fascinating quirks of the human mind.