Gramps: Well you’re not yourself, I’ll give you that. You just… you seem to be drifting, sweetheart.
Donna: I’m not drifting. I’m waiting.
Gramps: What for?
Donna: The right man.
Gramps: Oh, ho, ho same old story. A man!
Donna: No, I don’t mean like that. But, he’s real. I’ve seen him. I’ve met him, just once. And then… I let him fly away.
Gramps: Well there you are, go and find him!
Donna: I’ve tried. He’s nowhere.
Gramps: Oi, not like you to give up.
Donna: You’re right. Cause he’s still out there, somewhere. And I’ll find him Gramps, even if I have to wait a hundred years. I’ll find him.
Doctor Who, Partners in Crime (4x01) [Screencap]
I wasn’t the biggest Donna fan after her Christmas special, but I have to say this scene made me fall in love with her a little.