Dominic Papatola says the toughest thing about being a critic is surviving the middle. “Working the edges is the most satisfying part of this gig: Any critic who tells you there isn’t perverse fun in writing a really nasty review is either lying to you or so generous he really shouldn’t be in the business. And the experience of a truly sublime night of theater is worth enduring 50 bad ones. But what of those nights that are neither black nor white — the scores and scores and scores of shows that run in a spectrum from pretty bad to pretty good? Those are the ones that will kill you — or burn you out, anyway — and there are lots of them.”