Why do people stare at me without my glasses?

Like I remember I was on the bus one time because I had to go to this afterschool daycare center, and this one girl got on the bus and she was used to me having my hair in a ponytail and wearing glasses, how come she stared when I took my hear down and was wearing contacts? Also, another time, I was at the airport with my mom, and as we were in this cart where the employees there drive you around in, I saw that this one older guy who was walking around with a suitcase was staring at me as we were passing by. He wasn't looking at my mom. He was looking at me. Am I funny looking or what? I don't have pictures or anything, but why would people stare?