Now that I've had time to reflect on what I've watched, I want to discuss one debate among fans that's come to my attention: Joffrey Baratheon versus Ramsay Bolton.
These characters may not be the two biggest villains in the series, but they're probably the two worst human beings that we see in it. Both are sadistic, hateful chauvinists who disrespect their relatives, humiliate the disabled, abuse people physically and psychologically, torture and kill them for fun, and have babies murdered to secure their own political positions. They're both undeniably evil, but which one is worse?
Age seems like a good tiebreaker at first. Ramsay Bolton is a full grown man, but Joffrey Baratheon is only nineteen at the time of his death; if he was monstrous enough to give Ramsay a run for his money at such a young age, imagine how much worse Joffrey could've become if he'd lived longer. The fact stands though that he didn't, which gives him a shorter rap sheet than Ramsay. Also, it's pretty doubtful that Ramsay was any less monstrous as a teenager.
On the other hand, you can argue that Ramsay is at least partially the product of a harsh upbringing. Unlike Joffrey, who was born a prince and had a relatively stable family unit, Ramsay was the illegitimate son of a then-unmarried lord and he had to grow up with that stigma. He also had to spend his entire life under the threat of getting discarded if his father married and had a legitimate son. It's easy to imagine this making him bitter, perhaps to the point that he'd find joy in tormenting legitimate nobles like Theon Greyjoy and Sansa Stark. And of course, his father was a horrible person that he probably inherited his cruelty from and lives to spite. You can actually understand the reasons behind most of Ramsay's actions, as atrocious as they are.
Joffrey, in contrast, is just a spoiled brat with power. He was never mistreated or deprived of anything before becoming king. He just hates everyone because they don't show him the respect that he thinks he deserves because of his bloodline. Some of his cruelty is premeditated, mainly the things that he puts Sansa through, but he commits most of his worst actions on impulse in response to being humiliated. His behavior is also partially due to his parentage, since we see that his mother Cersei Lannister was an entitled little snot as well growing up. However, even she objects to Joffrey's behavior and is frequently threatened and undermined by him for it.
Think of Ramsay and Joffrey as ice and fire. Ramsay always manages to stay cool and calculating when he's angry, and thus his cruelty remains focused on just a few key people. Joffrey handles his anger like a volcano erupting; he doesn't think, he doesn't care, he doesn't focus, he just makes a mess. And when you have an entire military that's obligated to do your bidding, you can make some pretty big messes.
I think the best way to decide who's worse is by getting down to the bare bones of who these characters are. If you strip away all of Joffrey's power, he's a helpless punk. We see this from how easily his elders chastised him before he became king. For Ramsay, receiving power was just icing on the cake. He was already formidable before he became a lord -- which he achieved by killing his father, by the way -- and what made him so formidable was that he was always smart enough to know the most efficient way of tormenting people.
Why did he torment people before he had power? Because he liked playing mind games with them.
Most of the awful things that Joffrey did were done in front of a large crowd. He was insecure, so he liked to make examples of people in front of his subjects to discourage everyone from questioning his rule. Even when he did things without an audience, he usually did them to send a message to someone who challenged him.
Most of the awful things that Ramsay did were done behind closed doors. People usually weren't even aware of what he was doing at the time, and when it came to interrogating prisoners, he often took things a lot farther than his superiors wanted him to.
Joffrey liked being cruel as a means to an end, but Ramsay liked being cruel for the sake of it. I think that's more than enough to qualify him as the more evil of the two.
Congratulations, Lord Bolton. This is one battle of the bastards that you did manage to win.