Well, because I am not eager to open old wounds on this topic....lol...I will stick with what the experts say about what might factor in to passing or failing a wide variety of truth tests. There actually are numerous reasons as to why someone would not be a good candidate for truth testing. Personally the most significant reason in my opinion would be Misty's intelligence or lack there-of. No disrespect intended but there truly have been studies done on this subject. Misty quit school after the 6th grade and I find that very disturbing.
http://www.fas.org/sgp/othergov/polygraph/ota/validity.html
snip~Intelligence
Intelligence is an additional variable which potentially might affect detectability. The ability of intelligent subjects to anticipate questions may affect polygraph accuracy. One possibility is that intelligent subjects are less detectable because, if trained, they are able to anticipate questions and employ countermeasures. Another possibility is that because intelligent subjects better understand the implications of a polygraph examination, they will respond to relevant questions with heightened arousal when they are attempting to deceive (2o).
There has been relatively little research on intelligence and polygraph testing. In one of the few experiments which look at intelligence and detectability, Kugelmass (95) found no correlation between intelligence and responsivity on a peak of tension (POT) card test. On the other hand, research by Gustafson and Orne (65) found that motivation to deceive increased the probability of detection. Barland and Raskin (20) feel this is evidence of the potential role of intelligence. Barland and Raskins study (22) which compared detection rates among subjects of different education levels, found no difference. However, a separate analysis of the sources of false positive errors by Raskin (133) found that the majority of false positives occurred among subjects who had college degrees. Level of education, of course, is not a perfect indicator of intelligence, and there is a need to better understand these relationships...~end snip