Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
As You Like It contains two of the most cynical characters in Shakespearean literature: the "melancholy Jaques" (who sees the world as a place of doom and gloom) and the sarcastic and argumentative Touchstone (who is always pointing out how dumb people can be).
So, why the heck are we saying the play is "optimistic"? Well, despite the pessimism of a couple of characters, the play as a whole is pretty forgiving. In As You Like It, Shakespeare acknowledges that men and women can be nasty (like Duke Frederick or Phoebe), hateful (like Oliver), and foolish (like love-struck Silvius), but he also suggests that human beings are essentially good. As for those who aren't? Well, they can be redeemed. (Why else would Shakespeare stage the miraculous and sudden conversions of Duke Frederick and Oliver?)
Now, some people see a breezy title like As You Like It and think, "Gee, Shakespeare doesn't seem to take this play seriously, so why should I?" Call us crazy, but we think that, underneath Shakespeare's seemingly light and airy touch, the play considers some very serious and very big questions. As literary critic Anne Barton says, "it would be a mistake to think of As You Like It only as a fairy tale, a fantasy love and game-playing in the open air. The comedy is essentially serious, concerned to examine the nature of people, emotions, and ideas" (Introduction to the Riverside Edition of As You Like It, 402). In other words, we shouldn't be so quick to dismiss As You Like It as the fluffy pink cotton-candy of Shakespearean drama.