Perhaps the problem with adulthood was that you weighed the consequences of your actions too carefully, in a way that left you with a life you despised.
What is wrong with me, that even this fucking loser won't give me what I want?
For the first time, Ted imagined fucking Anna the way he (almost) fucked Rachel: cruelly, without concern for her comfort, fully acknowledging that as much as he loved her, he hated her, too.
Did he even exist in her mind, as a living, breathing, thinking person? He spent so much time trying to figure out what she was thinking, but what kind of a consciousness did she imagine lived behind the mask of his face?
And yet sometimes he'd lie awake at night imagining Rachel telling her story to a tribunal of all the girls who'd ever rejected him, regaling them about his deceptions, the way he'd pretended to like her when he didn't, the mask of 'niceness' he wore when the truth was he was a selfish, lying piece of shit—and he saw all those girls, Anna at their center, shocked but not shocked, nodding and agreeing that yes, of course, they'd known something was wrong with him all along.
Ted was wildly uncomfortable. He wasn't quite sure who Rachel was on a date with, but it didn't seem to be him. He'd contributed nothing to the outing; as far as he could tell, she could have brought an inflatable doll with her to the movie and had an equally good time.