Some who glorify evil imply that the only motivation to do good is lost when God is not in the picture. In a way this is true, because, as Jesus said, "I am the vine and you are the branches ... apart from Me you can do nothing." A universe without God a) would not exist, b) I would rather not exist at all in (I lost my motivation when I lost faith). But, the motivation, from Nietzsche's perspective (the first dude to say that "God is dead" thing), is fear (not reverential respect, but fear of punishment) of God, of hell. However, this is not what motivates a saved Christian. What motivates a saved Christian is that God loves us no matter what (that is all He was saying by dying for us). Evil (messing things up) is such a waste of time once you "find your motivation". There are those (secular humanists) who claim motivation without God, but... you know... I don't know how they do it... or if they even do (maybe their view of good is skewed (sp?)?). I just know... I personally never had that motivation after I lost faith [I became selfish to the point of narcissism (sp?)], until He found me. That isn't to say that I only ever do good since He saved me. It's just to say that, when I do good, it isn't motivated by fear of punishment, but by God's love. And, when I feel bad about doing evil (sinning), it isn't because I'm afraid of punishment, it is because I miss the closeness to God that I feel when I am living the way that makes Him smile.
God is the source of meaning (not all meaning, just the meaning that counts here). As the source, He requires nothing outside Himself. We require something outside ourself, we need God, because He is the source and we are not. More to the point, He made us that way, so that we could be loved; could love (because He's Love).
Why can't we be our own source of meaning (love)? May as well ask why we can't stop needing love. I used to find it really odd... that everything seems right in the world if that "special somebody" is around to pass the time... I used to think it was weird that we couldn't get along fine all by our lonesome... strange that we needed others and couldn't get that need met inside ourself.... why it hurts so much when that need is not met... so much that we can become numb to pain in self-defense. This is a powerful need. It is how it is... and it is that way for a reason... not by chance.