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.
10. Considering Letting His Ex Die (For Dumping Him)
Grey Hulk is often responsible for some more profoundly immoral things the Hulk has done in the past - largely because he's actually capable of sentient thought unlike most of his savage brethren, and so when he does something bad you know he's actively chosen to, instead of just following instinct.
Take, for example, the time Joe Fixit saw Marlo Chandler, his former girlfriend, being attacked by a werewolf. Call me crazy, but if you're a dude who can fight Thanos and not always end up in tiny pieces, you should probably help anyone being attacked by a mere werewolf, even if it's someone you aren't fond of.
Because the Hulk was still bitter that Marlo had broken up with him, he considered for a full moment leaving her to be mauled to death by a savage man beast as punishment for having the nerve to leave him. While he was upset he'd thought about it afterwards, it doesn't change the fact that it's a pretty messed up way to think about getting back at someone for dumping you.