capitalizing, or not, the first word within a quote

Something hard to remember (if you ever learned it):

http://englishplus.com/grammar/00000043.htm

Capitalize the first word in a quotation if the quotation is a complete sentence or if it is an interjection, an incomplete question, or fragmentary response

Correct: He said, "Why did you come back?"
(Quotation is a sentence by itself.)

Incorrect: She replied, "you wanted me to."
(A fragmentary response, you need a capital.)

A quotation is not capitalized if it is not a complete sentence and is part of the larger sentence.

Correct: I believe it was a "far, far better thing" to have confessed the crime.
(This quotation from Dickens is part of the larger sentence and is not a complete sentence in itself.)