I can understand the case where feedback provider holds back this thoughts when there is a fear that his or her name would be revealed and it may spoil a good relationship or cause unnecessary trouble in office or life.
But when the feedback is being provided for a good cause why do people shy away from giving a complete feedback? Why do they provide 180 degree feedback which only leads in a direction but doesn't complete the circle leaving the seaker to ponder all over for the correct point?
Take example of ADG performance poll. There are votes for good, ok and bad. Good and OK are understandable because it is kind of known as testing and many in house scenarios has proved that the performance is acceptable (if not great) in many use cases. But BAD was (kind of) unexpected because of so many hours of testing which has gone in.
Bad performance can arise because of many reasons. For example it can be due to bad performance of GroupingCollection as Doug has kindly pointed out. It can be due to complex custom itemRenderers being used. It can be due to a genuine problem in a particular control flow inside ADG. But without a complete feedabck (pointers to the exact problem faced if not samples) it would be impossible to work on anything. It would be similar to searching for a black coat in a dark room or worse for a non existent coat in a dark room.
This also goes along the same lines as my post about software patches. If customers don't make use of available source and public bug base and provide a good feedback even a very good intention/path provided to help customers goes waste.
In this context I don't know whom to blame for the situation as customers we find ourselves in, because we are not making full use of the easy avenues open in front of us to make a product worthy of the money we have paid for. Or is it that customers have accepted the situation and are showing indifference towards demanding what they rightly deserve?