No. 2: The Tragedy Of Hank Pym
While Hank Pym is clearly a genius in every sense of the word, his mind is also a fragile mess. His work in discovering Pym Particles and being a founding member of the Avengers helped him make a name for himself, but that good fortune would not last and his mind would eventually begin to crumble. There are various reasons for this. Hank he often felt inferior to fellow Avengers Tony Stark and Thor in terms of intelligence and physical strength respectively, which caused a significant lack of self worth, as well as the immense guilt he felt over creating the homicidal android known as Ultron who nearly destroyed the entire world.
These factors, among others, were reasons for his mind being such a mess, which lead him down a self destructive path and even caused an infamous comic book scene involving him hitting his wife Janet Van Dyne. There have been some who claim that Hank got a "bad wrap" and that it wasn't entirely his fault, but it is still an infamous moment for the character and within Marvel comics as a whole.