The following is proof that despite all of your preparation before trial, you just never know what a witness will say once they're on the stand.
Q. Are you familiar with the defendant's reputation in his community (Ft. Worth) for truth and veracity?
A. I guess that I am ...
Q. Just answer "yes" or "no."
A. Well, yes.
Q. Okay. Is his reputation good or bad?
A. It's about medium - sometimes he tells the truth and sometimes he don't.