You’re so proud of yourself when you finish, and so overcome with oxytocin (which scientists have dubbed "the cuddle chemical") that you're gushing about how great the sex was. You want verbal confirmation of a job well done, or a high five, at the very least.
If you peer into her eyes and say, “That was amazing" and she actively avoids eye contact and mumbles something about it being “pretty good,” it’s not because she’s shy. It’s because, in retrospect, she feels guilty for lying, but also knows it’s too late to go back. She’s conflicted, so she walks the line by acknowledging your efforts with a half-assed compliment, while ducking from your soul-penetrating gaze.
Just be thankful that she didn't shake your hand. Oh wait, she did? Ouch.