In my opinion Sasuke is just completely selfish in his motivations. He assumes he knows what others are thinking and that they could not possibly have any decent or understandable reason for doing the things they did. He says he's avenging his brother by attempting to destroy Konoha when he's really just venting his own frustration with what's happened. If he were to state his real motives I wouldn't dislike him nearly as much, besides Itachi never wanted Sasuke to harm Konoha. His actions alienate all who really cared for him and put them in really difficult situations.

And then there's the Mad Hatter. He always acted like a jerk, to Alice, to everyone. There is no real reason that Alice should have fallen for him except that he looked like her ex, and since it's been shown her ex was a complete cad that should have been even more of a turn off. While reading Alice in a Country of Hearts I assumed that the Mad Hatter would be used as a mechanism that characterized all that was wrong about her previous relationship, allowing to move on and leave Wonderland with a clearer outlook than before. Instead his Bad Guy allure, took Alice in and he kidnapped her rom the real world, bringing her back to the dream. In other words, he keeps her from acknowledging reality, and keeps her from moving on. And I think that's unforgivable.