Abigail worked for Elizabeth Proctor, and when Elizabeth discovered Abby and John were having an affair, she fired Abigail. Abby was resentful of that, for a couple of reasons. The first was that it denied her access to John, who she was very much not over. The second is because her getting fired tainted her repuation; rumors spread, and it is alluded to the fact that she couldn't find work. That is probably why she is livnig at her uncle's house (Reverend Parris) at the beginning of the play. So, there is conflict between Abby and Elizabeth even before the play began, over that issue. One other conflict that Abby has with Elizabeth is that Abby feels that John is being submissive to Elizabeth, and bowing down to her wishes and desires, when Abby wants John to forget Elizabeth and be with her. Abby expresses this to John, saying, "I marvel how such a strong man can let such a sickly wife" have control over him. Abby hates Elizabeth so much that we discover that she was drinking "a charm to kill Goody Proctor" at the beginning in the woods, and later framed Elizabeth for the needle stabbing with the poppet situation. So, Abby is seriously conflicted, wants Elizabeth out of the picture, and Elizabeth is resentful towards Abby and John for the affair, and has her own issues with Abby herself. So, the two of them aren't bff's, that's for sure. :) I hope that helps a bit!