Never take seriously what a theatre critic says. That’s never been more true than it is about The Philanderer, now playing at the Shaw Festival. Robert Cushman of the National Post tells chapter and verse about the plot but never quite gets around to saying whether he likes the play or not. At one point he even says he’s going to plagiarize himself from a 2007 review by joking he “would never have joined any club that would have me as a mentor.” Of course, Cushman is also sampling Groucho Marx, not just himself.