The type of criticism that you can express has a lot to do with the kind of relationship you enjoy. If it's close friend, you can sometimes express your criticism in a humorous way. Like "with all of my wisdom and experience I know I should shut up, but . . ." If the person is one with a more distant relationship, it is rare that they will take outright criticism well. But you can initiate a discussion by talking about a similar situation that you have experienced.
Deb