Girls, why would you ignore a friend request from a guy?

[Joshua1902]

So we used to hangout 1 year ago but something happend, she told my friend to say hi from her to me but when i tried to add her on a social media she left the request on pending?

[LUPITA00]

This one a bit hard for me personally, I would ignore it for
1) In a relationship and doesn't want to cause a fight
2) Maybe she was just being nice
3) maybe she hasn't seen it yet

[Joshua1902]

So a little info here,

I met this girl trough some friends, we were with eachother every summer so i would break this into different summers.

In the start she really didn't talk to me so much, she talked more to my other friends.

Summer 2: she started to try to talk to me more this time, she complimented me with saying i had pretty eyes, she started to laugh most of the time i answered her questions. She would also try to call me a hotwing. Her friend i think tried to tell me she liked me. They would try to get us both closer to eachother.

Summer 3: She started to take pictures of me when i had been thrown out of a boat. She would later those 2 days always ask me if i were ok, she would always giggle/laugh when i answered. She also started to ask teasing questions about it. But my friends said they didn't like being with her, so haven't seen her in 1 year now.

Now after 1 year with no contact she told my friend to say hi from her to me. So i tried to add her on social media but she just ignored the request and left it pending.

Why did she do this.