To summarize: Rand shows DO a pattern where the DO no longer exists. Rand is horrified by the world as everyone seems to have lost their personalities. Rand later decides not to kill the DO and instead reseal the DO to avoid this fate.
The idea really bugged me when Rand showed DO the pattern and I hated the plot of not killing the dark one. So essentially, every part of life that isn't kittens and babies is brought about by the DO? Every petty fight, disagreement, small vice are all called by the DO? Mat stealing pies from windows: DO made him do it. Rand breaking into barns and stealing eggs: DO made him do it. Gambling, drinking, arguing, fighting: all from the DO.
Just lost me when every little thing not puppies and kisses is caused by the DO and wouldn't exist but for the DO.