I felt a sympathetic pang of sadness when I first read this exchange:
“You’re welcome,” said Professor Quirrell. “I hope you will not object if I go on making him a particular focus of my attentions.” Professor Quirrell’s face was now very serious, and very still.
Dumbledore looked at Harry.
“It is my own wish also,” Harry said.
“So that’s how it is to be…” the old wizard said slowly. Something strange passed across his face.
There was something very disheartening about Dumbledore, who thinks in stories, realizing that he was being written out of the book. He would not get his last major role in his final act as the Mentor of the New Hope For Good. That would be Quirrell. Dumbledore’s story was over. I like Quirrell much more, but I still felt bad for Dumbledore.
But it turns out he still gets plenty of screen time in later chapters after all.