quickly, the answers
The quote: "I can't do that. It's really hard for me to let things go."
I guessed: Nearly every member of the cast except --
Who said it: Andy (Ed Helms)!
The quote: "So I googled 'how to deal with difficult people,' and I got all of this. So we're going to try some new things today."
I guessed: Michael, because he's always googling things.
Who said it: Phyllis (Phyllis Smith)!
The quote: "If you want to win, you've got to fuel like a winner."
I guessed: Jim, playing a prank on Dwight.
Who said it: Dwight himself.
The quote: "It appears that the Web site has become alive. It sometimes happens to computers and robots."
I guessed: Dwight.
Who said it: Dwight!
At least I got one right, right?