How should a person adjust to a world they did not create?

Really one needs to put everything into context. Holden saw things in black and white when really life is many shades of grey. We do the best we can under the circumstances working to change what we can and accept what we can't change. I think that Holden's sister Phoebe is an example for Holden. She has an innocence and keen intellect that Holden admires. She can still laugh and play. If anybody can pull Holden out of his pit of despair, it's Phoebe. The merrry go round scene at the end of the book is poignant and gives us a little hope for Holden.