May i add to this, that there are two types of criticisme..

The first one is seen much to often on the interwebs or in real time life, and thats the kind of criticisme to burn someone down.. it doesnt require much tought, just some fierce words..

However there is also the kind of criticisme Hammer describes, the kind of criticisme to better someone, that gives someone insight in their weak points and gives them advise how to improve..

One type of criticism should allways be welcomed by everyone
The other type should be banned out...