Doctor Doom has a special Hatred for each member of The Fantastic Four. The Fantastic Four are the only thing between Doom and world domination. The Fantastic Four have managed to hold Doom off many times, but yet Doom returns. Although the best efforts of the Four are troublesome, Doom has managed to defeat them many times.
Mister Fantastic, Reed Richards, is the ultimate super-villain in the Marvel universe. Doom's efforts to take over the world are in good
judgment, but Reed insists on foiling Doom's every attempt. Doom's reign would end world hunger, cease violent conflicts, and ensure peace for all the inhabitants of the world (with exceptions). Reed Richards does not understand the need for a leader such as Doom. I believe it to be Reed's envy (of Doom's genius) that makes Reed want to stop Doom. Doom's reign would not be a dictatorship; It would be an enforced monarchy. All people would be happy, for it would be the law.
The Ever-Lovin' Blue-Eyed Thing, Ben Grimm, Reed Richards' mindless follower, is yet another force between the world and the peace it so well deserves. The Thing mindlessly follows Reed, and spats off comic relief such as, "It's Clobberin' Time!" Due to Thing's goofy nature, Doom hates him. Also, in one of Doom's efforts to bring world peace, The Thing crushed Doom's armor and left Doom helpless. A smarter villain would have killed Doom, but The Thing did not. Now revenge will be Doom's, and The Thing will wish he ended Doom's life.
The Invisible Woman, Sue Storm/Richards, is stupid enough to marry Reed Richards, so Doom loathes her insolence. Doom forgives her somewhat; because she's hot. Doom likes the ladies.
The Human Torch, Johnny Storm, is also a villain that Doom does not appreciate trying to foil his attempts at domination. As The Invisible Woman's brother, The Human Torch is always meddling around with the big kids and getting in the way. Doom's loathes his insolence, and spits on his flame.