Jane Foster was exposed to science since she was born. So, she had a great love for it. Jane is a very intelligent woman, and is a free thinker. Nothing is ever set in stone, and something worth working to discover. She is all about doing the research herself, and doesn't think of the risk. This even means she is willing going into zero-visibility conditions; among all other things she found herself in.
Friends: Jane is a very dedicated to her work and research. So, friends have been probably more few and far between, unless they are in the same field she is in. Erik is more like family to her then just a friend and colleague. Darcy Lewis was her intern when they first came into contact with Thor. Jane is very much a kind person, and is a loyal friend anyone could have.
Enemies: Jane despite her very kind personality, and loyalty to friends. Most likely like any other person in the world would have some enemies. Be it the kind that has a jealousy for her intelligence, experiences, and the fact that she is close to Thor. She has them, and anyone that goes against humanity be it earth or other worldly are her enemies.
Lovers: Jane has had problems with relationships and research. It normally pulls from her relationships, and it normally ends. Like the relationship with Donald Blake. Falling in love with Thor in the time spent with him. And even as he had promised to return to her. Jane has been more determined to be with Thor, even if that meant her finding a way to get to Asgard just to be with him. Jane was more than happy when Thor returned to be with her.