We're just going to come right out and say it: John's mom, Anne, is hard to like. Phew. It's good to get that one off our chests.
On the one hand, we feel for Anne because her hubby ran off and never looked back, leaving her in a rut of depression and loneliness. We totally get why she has trust issues after dealing with that guy. But on the other hand, she doesn't do much for her son after the divorce. Sure, it might just be his (jaded) perspective, but the way he puts it, she abandoned him pretty much as much as his dad did.
See, Anne didn't both trying with John. She just left his dad to deal with him—which he, of course, didn't do—and she even stopped touching her son completely. It's no wonder John's messed up. Listen to how he describes her actions in his letter to her:
For years I made up excuses for you, and tried to convince myself you didn't really hate me as much as you hated Dad. But the evidence didn't confirm it. (10.58)
We know he's going for jugular here, but he still has a point: John reminds Anne so much of his dad, and she lets this cloud her feelings for him. It's a major bummer. And as far as John pushing people away in response to getting hurt, well, we'd say the apple doesn't fall very far from the tree when we look at his mom.