What's up with the FU signs in Chapter 25? "That's the whole trouble. You can't ever find a place that's nice and peaceful, because there isn't any. You may think there is, but once you get there, when you're not looking, somebody'll sneak up and write "FU" right under your nose. Try it sometime."
First, I love how Holden is concerned about young children reading the FU signs, even thoug Holden manages to swear more in a paragraph than South Park.
Second, I think Holden knowing that marking up places with FU is terrible and immature is another stab at showing why Holden is so messed up. I think Holden's problems started back with Allie and D.B. Holden was the odd child out and has yet to come to terms with allie's death. His caring about who is influenced by some delinquent's FU on the wall backs up his desire to be the "catcher" waiting to save the children in the rye field, to keep others from going through what he went throgh.
Holden, concious of it or not, wants to help the youth of tommorow. :)
