True, more constructive criticism would be better. As in 'your guard work sucks' or 'you suck because your footwork is too linear'.She just saw me spar, and opened her big mouth after to tell me that I suck.
Unfortunately, even this level of criticism, is too much to ask of most people. Let it go. The most important type of criticism is the stuff you seek out from those who know the subject.
Criticism is useful if it helps you learn, and useless if it just cuts you down. Still, 'Your great' is the worst type of criticism if you think about it ....