I disagree with CubDriver's last point. I think its your job as a CFI to try your best to work with a difficult student and try to find a way to help them learn. I wouldn't sign anyone off for a checkride who isn't ready-- but -- you should try your best to help the student who is having a hard time achieve his goal. If you give up on a student-- they will quickly lose whatever self-confidence they have and never improve. Give each student your best! You owe it to yourself! And again- congrats on your CFI-A!!!