I think that most of the time on this board if people have a negative opinion they just don't share it. This of course creates a chain where everybody is a little scared to give an honest opinion.

I personally don't give my feedback on tunes so much, as I have no idea about producing, but I always try to give my opinion on mixes that people post, whether it's good or bad.

If it's bad though, I always try to be constructive in my criticism.