I have come accross a pretty broad spectrum of instructors during my time range from the plain disinterested hour builder to the first class career instructor. Sadly there are to many of the former and nowhere near enough of the latter.
I have no time for the self important think they know it alls with 300hrs under there belts waiting for an airline job. And in a quite a number of instances being the CFI has done nothing other than make an average instructor even more self righteous. Donning the CFI hat does not suddenly make them into a "skygod".
The standard of instructor is way to variable. As with many subjects I have to agree with IO540!