Now it's just my theory, but maybe you watched Death Note thinking the intention was to paint Light in a positive way. I tend to dislike characters when they either mess up the storyline, are boring, or are depicted in a way I disagree with.
Maybe if you rewatch with the mindset that Light is not meant to be looked up to, he won't piss you off as much.
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SuperNiceDog - 1, pjbasis - 0