The poem "Country Fair" by Charles Simic centers around a dog with six legs. I'm sure the dog is supposed to symbolize something important that the speaker feels the presupposed audience is dismissively claiming non-existent, but I'm not sure what that thing is. I've seem claims that the dog is supposed to represent Yugoslavia, which would be consistent with Simic's other writings in terms of being Yugoslavic-focused, but I can't reconcile that with the idea that the speaker expects people not to believe the dog exists ("If you didn't see the six-legged dog, it doesn't matter. We saw it..."), and that expectation of disbelief seems quite clear to me in the work. What does the dog represent, and if it's Yugoslavia then how can that be reconciled with the expectation of skepticism?
Evidence for an expectation of skepticism, as requested:
The poem is framed as a retelling of an event by the speaker to a listener. The speaker opens with "If you didn't see the six legged dog,/It doesn't matter./We did, and he mostly lay in the corner." This phrasing, "If you didn't see X, it doesn't matter. We did" is confrontational in both tone and nature. It seems almost a response to the common backhanded statement of disbelief, "I didn't see any...". And indeed the speaker appears to be engaging in that sort of speech by which one attempts to assert the authenticity of one's perception of events as real-- that is, real in defiance of either alternative contradictory interpretations or rejection of the experience therein asserted: the speaker begins with the aforementioned combative language, details a series of events that further entrench their position of authority: "As for the extra legs,/One got used to them quickly/And thought of other things" (If you had seen the dog you would not think it strange any longer that it had six legs. Your preoccupation with the number of legs is a distraction and foolish thought stemming from your naivete), and then finishes by preempting any further discussion of what happened with "And that was the whole show.".
This confrontational, almost aggressive language belies a speaker who does not expect to be believed, listened to, or to have their experience validated. It's very defensive, and seems intended to preempt insistence that they must be making up this six-legged dog.