People get in your face for several psychological and social reasons:
As an aggressive, territorial move to establish dominance, often a power play, trying to assert control in the interaction.
Due to different cultural or personal space norms people raised in dense environments or certain cultural backgrounds may have a smaller sense of appropriate personal space, causing them to stand closer than what feels comfortable to others.
Lack of awareness about personal boundaries, or realizing they’re making others uncomfortable by standing too close or leaning in during conversations.
Getting in someone’s face can trigger a stress response, activating the fight-or-flight mechanism, which makes it an effective way to intimidate others.
These movements can create a sense of belonging or connection.
Touch and proximity can communicate that we belong together, and this becomes uncomfortable when the feeling isn’t mutual.
When someone invades one’s personal space they might experience physical reactions like an increased heart rate, sweaty palms, and an urge to back away.
For most people, intimate space extends up to 18 inches from your body and is reserved for family and close friends.
When strangers enter this zone, it can feel particularly threatening and uncomfortable.