[He might loiter a little, but he always buys the books he reads, and more. He feels bad about it though, especially when she says that...]

I... I lost track of the time again, uhm, I'm-- sorry. I... should put my phone on... a timer when I come in here, or-- or something.

[It's not a joke, but... He thanks her when she brings out two cups of tea, blushing a little.]

You... y-you're very kind.