I'm aware that, in writing, repetition is sometimes bad. For example:
"You forgot my birthday!" I said.
"No, I didn't forget your birthday."
"Then why didn't you wish me happy birthday?" I said.
"Because I didn't want to embarrass you. You know, make you feel special and all that."
(Note: I just came up with this dialogue. Probably the worst piece I've ever written in my life.)
But when is repetition good?
These are examples from my own writing. (I thought the repetition was good. But I'm not sure anymore.)
Mike called me that weekend. To be honest, I'd been trying to avoid him. Not because I was pissed at him, but because I was starting to develop feelings for him---which I guess pissed me off.
"The mind is a part of the body. More specifically the brain. That's why there are cases of head injuries where people had lost their capacity to recognize objects, faces, feel guilt or anger. Which is proof that our consciousness isn't really separated from our body. It's just feels that way. Anyhow, this notion is going away, especially now that we can literally look inside the human mind."
"I wish we could look inside the cat's mind," I said. "We'd know what's wrong with her at once."