The only quote featuring C.C. about a meaningless life that comes to my mind is from ep. 7:
Lelouch: I was dead until the moment I met you. A powerless corpse which was lying to itself and pretending to live. A life that lives without doing anything... it's the same as slow death. If I must live as I did before, then... C.C.: Wait. True, there is no meaning to a life like that.
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Lelouch: I was dead until the moment I met you. A powerless corpse which was lying to itself and pretending to live. A life that lives without doing anything... it's the same as slow death. If I must live as I did before, then...
C.C.: Wait. True, there is no meaning to a life like that.
Did I guess?