One of the fundamentals of check rides and flight tests is to determine the testee's performance to a standard. If you give it a moments thought, you realize that it is because we are not good at self evaluation.
I found that AOPA article very interesting, and to quote from it again, as Hedley already did
Does he raise his voice or make inappropriate comments? This is a big one. There's no place in the cockpit for tempers, yelling, destructive comments, or anything else that makes the student feel uncomfortable. This is one area in which the student doesn't need to seek out advice, talk to the chief instructor, or wait it out to see if things get better. If the instructor makes you uncomfortable, drop him.
Now lets look at instructors. The fact is they are no better at self evaluation than the rest of us. In fact, if one does not subscribe to the above advice, they might just be able to rationalize in their minds all the reasons it is OK to ignore it.
Personally, my opinion is that any instructor who resorts to yelling at a student, for any reason whatsover should be taken aside by their CFI for a little chat...it is obvious that they just dont really understand what instructing is all about.
As to the original post, there are, unfortunately two sides to the story. If your instructor is spending a little to much time on exercises that are not on the curriculum, or handling the controls far more than necessary, it is really time to change. It is not about hard feelings..just say you would like to experience a different instructors technigue because you are having difficulty learning.
From what I have seen in flight schools in the last few years there are alot of instructors who do too much flying themselve, demonstrate and then test the student without giving the student any time to practice.
The result is students get into the circuit before they can properly manage airspeed control for example, where they spend several hours learning it one circuit at a time rather than two partial lessons in the upper air portion.
There is also a tendency of some instructors to go flying before the studen has being properly briefed. Again, a misperception by the instructor as to what the student has actually learned.