When a hasid of Satmar told him that Reb Yoel was the messiah he retorted: "If you were to say that R. Yoel is a great scholar, I would agree. I would also endorse the view that he is a tzadik, a giant among men. But to assert that he is the Messiah, this is ridiculous and preposterous. How could we face the world with him as the messiah?"I was originally going to make this a "name this quote" contest (complete with a real, honest-to-goodness prize - a hagiography from CIS Publishers.) But I waited too long to post and Google Books has since made available a preview of the book wherein this is found.
He then explained the influence by which R. Yoel wielded such power over such large masses of chassidim in this way: "The owner of a 5th Avenue store is not necessarily superior intellectually to a shopkeeper in the Bronx. The former was just lucky and fortune smiled upon him."
He found it incomprehensible that the Rebbe of Satmar forbade his followers to visit the Western Wall. "If he lived in Israel," said R. Itamar, "he would visit the Wall. Only in heaven is it known who is a genuine rabbi."
Source: Hasidism in Israel: A History of the Hasidic Movement and Its Masters in the Holy Land by Tzvi M. Rabinowicz.