SAO was pretty terrible, but there are plenty of worse things out there. Probably the worst thing I've ever seen was Chaos Dragon: Sekiryuu Seneki. I watched it as it aired during the Summer 2015 season. It was torturous to watch.
Edit: those of you who actually enjoy SAO need to watch something good. Yes, the first half of the first season wasn't all that bad, but everything after is complete trash.
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11eyes was pretty flippin' bad. I watched the first few episodes of some other anime that was extremely bad, too. It was some stereotypical school anime where the MC is pervy as frick and is apparently OP. Art style was awful too.