Some of the best quotes to show Abigail's blindness to the truth concern her feelings for Proctor.
In Act I, when Proctor and Abigail are alone, it is clear that she is trying to rekindle the spark between them. She shows an inability to confront the truth when she speaks of what she sees as meaningful sexual attraction between them:
I know how you clutched my back behind your house and sweated like a stallion whenever I come near! Or did I dream that? It’s she put me out, you cannot pretend it were you. I saw your face when she put me out, and you loved me then and you do now!
It is clear that Abby cannot see the truth. She is incapable of recognizing that their affair is in the past. Proctor has moved on, while she displays an unwillingness to do so.
Once sexual rekindling fails, Miller suggests that Abby uses emotional dependency to block out reality. After Proctor repudiates her, Abigail suggests that she "has seen him" at nights since Elizabeth fired her:
And you must. You are no wintry man. I know you, John. I know you. She is weeping. I cannot sleep for dreamin‘; I cannot dream but I wake and walk about the house as though I’d find you comin’ through some door. She clutches him desperately.
Miller's inclusion of "desperately" clutching Proctor shows how Abigail is blind to the truth. She uses tears as a way to create a sense of guilt or sympathy in Proctor. As a result, she is incapable of understanding that Proctor no longer has feelings towards her.