When you take an uncontrollable berserker, and give him five tons of muscle, make him practically invulnerable and immortal, and pop on some nice green skin for seasoning, you're in for a wild ride. The Hulk has consistently provided a rollercoaster from Hell during his time in the comics, being both a hero involved in some of the most badass fights in comic history, and also a terrifying menace at the same time.
Though most of the Hulk's worst deeds are done when he's raging out, a surprising number are done by a pretty coherent green giant, proving that he is one of Marvel's most unpredictable entities. He can save the world from a gamma bomb or world-destroying threat, but he can often present just as much of a danger to the Earth he just risked his life protecting.
All in all, you have to feel at least kind of bad for Bruce Banner, as the poor guy is strapped in the the madness of his green alter ego, unable to do anything but repeatedly apologise after all the damage is done.