Definitely Canada. After having them ask me every time I go there, "why do you want to visit Canada?" (not to mention lots of other insulting questions), I started asking myself the same question, and now look elsewhere for my vacation plans (having said that, I would encourage anyone that has a similar experience while entering the US to ask yourself the same question). As if that wasn't bad enough, I always get the worst treatment from US immigration whenver I return from Canada (my favorite question: "did you use any illegal narcotics while you were in Canada?").