These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Into the Woods
Alternative Character Interpretation: Are the Princes well-meaning guys with bad impulse control, or sleazy, manipulative bastards who take advantage of any opportunity to get laid? Or some combination of the two? The script leaves them open to played in both ways, including anywhere on the spectrum between them. This is especially the case for Cinderella's Prince, who gets more screen time and has more impact on the story than his brother; he's very quick to jump on the Baker's Wife, but he does genuinely seem to care about Cinderella.
Chorus-Only Song: "Children Will Listen" actually has a short introductory verse that was not used in any of the main productions. However, it was recorded for the revue "Sondheim on Sondheim" and singers occasionally use it when recording the song on its own.
Fetish Fuel: Ooh boy. Something for everybody: the wolf for furries and vorephiles, and the giantess ("drew me close to her giant breast") for macrophiles.
Why is Cinderella's prince so sick upon the sight of blood in the slipper? It's his thing about blood.
Why did it take the Giant's wife so long to seek revenge as Act 2 takes place at least 9 months after the third midnight in Act 1? The first beanstalk grew from 5 beans which increased the potency of the magic and power. There was only 1 bean for the stalk that the Gaint's wife took. It took a while for it to become strong enough to grow that tall.
Fridge Horror: The characters are trapped in a circular time loop. At the end of Act 2, the Baker begins to tell the story to his son, using the same words the Narrator used in Act 1. In essence, he becomes the Narrator. This does not bode well for his future happiness - or that of his son, who would of course, become apprenticed to work in the Bakery, when he becomes old enough. They're all condemned to repeat the same story, over and over again, for ever.
Averted in that they can avoid the mistakes of the past and atone for them. The Baker, for one, isn't abandoning his child unlike what happened with him.
Interestingly, in the 2012 Public Theater Shakespeare in the Park production, the Mysterious Man is played by Chip Zien, who played the Baker in the original cast.
Jerkass Woobie: The Witch may be mean, but the interactions with her and Rapunzel...
Narm: It can be a little hard to tell whether "Agony" is supposed to be a serious song or not. The Princes certainly sing it dramatically, but the subject matter (mostly rather mundane infidelities and moral dissonance) tends to make it comes off as ridiculously melodramatic. This may, of course, have been the point.