private students are quite different than instrument and commercial students.. many IFR and CPL students understand the value of a good walkaround and preflight, as well as a good understanding of the weather.. what chaps my ass is that some CFI's see a student finishing too quickly (PPL in 45 hrs, vs 60) and they feel they need to build up more time with them in the airplane, even though they are more than proficient...
more times than none, the student really does think something is wrong and get down on themselves because they honestly feel something is wrong with the way they fly.. add a few thousand dollars on top of that and you might as well take the dream from them

for my instrument, i had a CFI say he wanted to spend another 10 hours in the airplane with me (at 140 an hour) and then he would sign me off for the checkride, when in fact the chief instructor gave me the ok three weeks prior and gave his checkride to ATP standards instead of just IRA PTS standards, just to ensure precision...

in this case, the guy really tried to dog me out of 1500 bucks and i took myself elsewhere, and then PASSED the checkride, even though the CFI said it was impossible at the time...