There could be various reasons why girls might be looking at you when you're not looking. They may be trying to catch glimpses of you without being too obvious.
Curiosity: If you're in a social setting or a public place, people often glance at others out of curiosity. It's possible that they are curious about you for some reason.
Non-Verbal Communication: Sometimes, people use eye contact to communicate non-verbally. It could be a way to express friendliness or indicate a desire to engage with you.
Observation or Evaluation: People might stare when they are observing or evaluating someone, especially if they don't know the person well.
Coincidence: At times, it might be coincidental that you notice someone looking at you. People's gazes naturally wander, and you might happen to catch their eye by chance.
Misinterpretation: It's possible that you might misinterpret someone's glance as staring. Sometimes, people might be looking in your general direction without actually focusing on you.
Admiration or Adoration: In some cases, people may look at others with admiration or adoration, perhaps due to something you did or said.
Cultural Differences: In some cultures, making eye contact is considered normal, while in others, it might be seen as impolite. Cultural norms can influence how and when people look at others.
It's essential to remember that interpreting someone's gaze can be subjective, and people may have various reasons for their behavior. If you're unsure about someone's intentions, the best way to understand them is through open and respectful communication. If someone's staring makes you uncomfortable or if you feel it's becoming excessive, trust your instincts and consider setting boundaries or addressing the situation directly if you feel safe doing so.