Headscratchers / Dear Evan Hansen

• Why did Connor keep Evan's letter?
  • The most popular fan theory is that Connor wanted Evan's letter to be found with him - it's mentioned that it was found folded up in his pocket when he could've just thrown it away and/or ripped/crumpled it up, especially if he was as offended by the content as his reaction suggests. Fans believe that Connor may have read it in full later on, realised it articulated what he was thinking/feeling almost perfectly, Zoe part notwithstanding, and didn't bother to write his own note because of it, and simply didn't consider or didn't care about the fallout it would have on Evan. He was about to kill himself, he had absolutely no F's left to give.
  • More mundanely, Connor simply either forgot about it or didn't care - he may NOT have even cared enough to read the letter in full at all and therefore had no idea of what the ramifications would be. That being said, I haven't read the book in a while, where Connor sticks around as a ghost for a bit and sees the whole mess that occurs almost entirely because he kept Evan's letter on him, so maybe our answers to these questions are in there.
• At first, Zoe questions Evan's story of being friends with Connor because she saw Connor shove Evan at school. Evan explains that Connor wanted to keep their friendship secret, and so shoved Evan because he was angry Evan spoke to him at school. But Zoe - and everyone else in the musical - doesn't even wonder why Connor signed Evan's cast. If (imaginary) Connor was so invested in keeping the friendship secret, signing his name on Evan's cast seems like a silly way to go about it.
  • The Fridge page points out how part of what makes Evan's initial lie so harsh is that it would've fallen apart if the Murphys had thought about it for just a few minutes - like how his arm would (likely) still not be in a cast in September if he broke it "end of May or early June". Yet they overlook these little discrepancies because they want to believe Evan's story so badly.