I would one-box in Newcomb's problem, but I'm not sure why Omega is more plausible than a being that rewards people that it predicts would be two-boxers. And yet it is more plausible to me.

When I associate one-boxing with cooperation, that makes it more attractive. The anti-Omega would be someone who was afraid cooperators would conspire against it, and so it rewards the opposite.

In the case of the pre-migraine state below, refraining from chocolate seems much less compelling.