Well to me, hugs (physically, in person, face-to-face) are one of the few friendly, yet intimate signs of affection that cannot be replicated or come close to the real interaction outside of seeing and interacting face to face with the person. (Sure, someone can say they hug someone or show their affection virtually or outside of face-to-face interactions, but it's just not the same.) While a "hug" isn't necessarily an tangible object, it is rather an action, gesture of kindness at that, and I try to tangify (probably not a real word, but whatever) it as like receiving a gift of some sort.
Also, it depends on the person that I'm receiving from. If it is a person that I admire greatly, is of value to me, or important to me (based on my values and perception), then it means so much more. Now that isn't to say that getting a hug from another individual is insignificant, there is some worth to that, but just much less than say, a celebrity or someone I really look up to. (Well, this is just the basics, but there are more factors that go into it so it's a bit more complex than what's on the surface.)
A few other reasons that just came to mind is that perhaps she just doesn't know me well enough, sometime in the past maybe there was a bad experience and she somehow associated it with me, or she just doesn't like me due to my awkwardness or something. I'm not sure if it were those reasons, but I'm not leaving any stone unturned.
Anyways, she isn't that important to me, but I thought this might be a good example of one of the many failed interactions I had with people.