#robert baraheon

When it comes to achieve a desire, they are the same;

“Arya was a trial, it must be said. Half a boy and half a wolf pup. Forbid her anything and it became her heart's desire.” -ACOK Catelyn VII

“Tell Robert Baratheon he could not, should not, or must not do a thing, and it was as good as done.” -AGOT Eddard VII

Their hatred Targaryens and Lannisters made them to decide wrong(?) choices which they questioned themselves later;

“Ned did not feign surprise; Robert's hatred of the Targaryens was a madness in him. He remembered the angry words they had exchanged when Tywin Lannister had presented Robert with the corpses of Rhaegar's wife and children as a token of fealty. Ned had named that murder; Robert called it war. When he had protested that the young prince and princess were no more than babes, his new-made king had replied, "I see no babes. Only dragonspawn."  -AGOT Eddard II

“Once, when there had been only half as many heads, Gendry had caught Arya looking at them. “Admiring your work?” he asked. He was angry because he’d liked Lucan, she knew, but it still wasn’t fair. “It’s Steelshanks Walton’s work,” she said defensively. “And the Mummers, and Lord Bolton.” “And who gave us all them? You and your weasel soup.” Arya punched his arm. “It was just hot broth. You hated Ser Amory too.” “I hate this lot worse. Ser Amory was fighting for his lord, but the Mummers are sellswords and turncloaks. Half of them can’t even speak the Common Tongue. Septon Utt likes little boys, Qyburn does black magic, and your friend Biter eats people.” The worst thing was, she couldn’t even say he was wrong.” ACOK Arya X

In neither case was Robert or Arya the main character committing the crime. But one approved of it and the other helped. Of course, Arya was a child and felt extremely helpless. But she was not too young to think about the consequences of her actions. She did it because it was an opportunity to get out of trouble. When she saw the consequences, she admitted her mistake.

On the other hand, Robert should have taken more responsibility as an adult. Ned was always the one to show him his mistakes. Just like Gendry showed Arya. Robert realized this again on his deathbed and tried not to make another mistake;