I think pride is a good answer. However, I could argue another of Harrison's flaws is he lacks vision. The plan he had to overthrow the handicap general and the current system of extreme equality was a noble one, but the plan was not well thought out. He needed to be sneakier than to burst onto national television and declare this war. This is where his pride got in the way and what led to his demise. But also if he would have been more clandestined in his plotting and planning to take over, rather than brashly announcing it, he could have been more effective at recruiting an army of supporters on his behalf and pockets of followers throughout the land, so that if he did fall, his entire cause would. His methods then were both short-sighted and egotistical in his thinking he could succeed in revolting all by himself.
I agree with others in questioning Harrison's methods of rebellion. If he really was so intelligent, he should have realised the futility of his actions on the television screen. A person as gifted and skilled as he was should have realised that the only way to oppose such a system would be through keeping his head down and disappearing, fighting from the shadows, rather than going out in a blaze of glory and changing nothing.
In most societies, what Harrison did would make him a hero. He was imprisoned for nothing more than being himself, and he does what he can to overthrow the tyranny of "equality." His methods are impetuous and ill-conceived, mostly because of his youth, but he does remind the rest of the world that there can still be freedom and beauty and love. It doesn't register, even with his mother, but the message has been sent nonetheless. His biggest flaw is his youth; with some maturity, Harrison may have been able to be more effective in his attempt to thwart the government.
I agree with post #2. I do think that Harrison is guilty of his excessive pride. While it is true that he was weighed down by so many handicaps, when he takes the opportunity to rebel against them, he declares himself the emperor and assumes that he would be the best leader in a world where people have no handicaps. He may be right, but he has no way of knowing this or of finding it out.
I don't see Harrison Bergeron as being prideful. He is a young man who has been weighed down with "handicaps" and who has been jailed. I don't see him as having a major flaw. He simply broke out of jail and decided to "buck" the system and take over the television station. I saw that as very brave, actually. It may not have been super smart to do what he did because it got him killed; however, he died happy and doing exactly what he wanted to do...dance with his beautiful ballerina.
Harrison's main flaw is probably his pride. Harrison was extremely intelligent in the world of general acceptance and neutrality. In the society of the story, Harrison was so exceptionally smart that his handicaps, items worn by governmental order to decrease his God-given superiority, were greater than any other person's. Harrison escapes these handicaps and his prison, grabs a ballerina who also was heavily encumbered with handicaps, and removes her handicaps so that she can dance beautifully. He then declares himself the emperor. His pride kept him from remaining low-key and possibly subverting the government that way. Instead he felt invincible due to his intellectual superiority and of course, that led to his death as he and the ballerina made easy targets for the Handicapper General. He also wasn't much better than the government he was thumbing his nose to - the government forced people who had any natural gifts or talents to wear handicaps in their attempt to eliminate competition and anyone feeling inferior to another. They were tyrannical. Harrison, by declaring himself emperor with no say allowed to anyone else, was doing the same thing.
I agree with #3. Even though Harrison dies, I don't see the story as a tragedy. Vonnegut was making a point about individual freedom of expression, not about totalitarianism in general - that territory had been covered many times by Orwell, Huxley, and Rand by the time he wrote Harrison Bergeron - so for Harrison to take up with some underground band of rebel activists would have led equally to the diminution of his personality. Instead, he fulfills his own wishes by any means necessary. In this way, he is redeemed and then martyred before millions of viewers.