"Dear Evan Hansen" is a canonical example of "Second-Act Syndrome," in which a promising thought falls apart somewhere after the entr'acte. The first act has several exciting moments; a troubled kid stumbles on a bad idea, and then the idea grows and grows, and there seems to be no way out of the mess. Unfortunately, in Act Two, the writers feel they *do* need to invent a way out of the mess, and they clearly get bored, and you get bored, too, because you're sitting in the audience. That said, I'll remember "Dear Evan Hansen" for a few good reasons. The writers studied Rodgers and Hammerstein; they open with a scene-setting number that grows straight of the mighty trunk that is "O, What a Beautiful Morning." The song--"Does Anybody Have a Map?"--isn't especially original, but it sets a tone (anxious, funny), and it throws us into the world of two interesting families; we're hooked. The writers also do a fine job wi...