At the surface level, mostly petulance, frustration and a need for vindication, recognition, and/or acknowledgement ("you were right and great and we were wrong"), and then revenge on them for not giving him that.
Below that, usually fear (of not being right, not being wonderful or better than them all, of being insignificant or on the "wrong side of history" and forgotten, of having to die with dreams unfulfilled, and be forgotten like 99.999999% of people are within a few decades), maybe desperation (if he cant see how else he can get what he so desperately wants except by ultimately falling back on this all-or-nothing stand?) and in the psychological sense, hostility (meaning, probably knows its not going to really get him what he wants but knowing that doesn't help him to actually get on with things that might get him what he wants).
Possibly narcissism and delusions of grandeur somewhere in the mix as well ("I'm cleverer, I'll make it work, nothing they say will happen, I'll outwit them, and they'll have to admit they were beaten")