My best line came from an informal tasting In hosted a year or two ago when I won the NB forum Christmas beer pass. It was " your beer smells like oatmeal cookies, but tastes like ass"
One thing I have noticed has not been mentioned in this thread yet, and it is no excuse for judges. Sometimes due to poor management of a competition judges have to judge two flights of above average alcohol content beers, and the comments on the second flight beers may suffer due to this.
I have had to judge both 16 a-e (Belgian and French ales), and India Pale Ale a-c on the same day, and when the 16 flight is dominated by big "E's" (Belgian specialty) and IPAs are mostly American and imperials the comments got a lot sloppier than I wanted them to. But then again so did my overall attitude