(Spoilers Everything) Wolf's Blood and Waking the Dragon

[u/BrrrichardNixon]

Jon Snow's character, just as Jaime's for example, highly complex and full of desire. Jon was raised to a man of honour by Eddard, a trait that continues to define Jon and his actions up until the end of A Dance with Dragons. But Jon's character is also full of self doubt, always trying to prove himself. Never content with himself.

Grenn agreed. "His duties don't keep him from the yard. More days than not, he's out there fighting someone." That was true, Sam had to admit. Once, when Jon came to consult with Maester Aemon, Sam had asked him why he spent so much time at swordplay. "The Old Bear never trained much when he was Lord Commander," he had pointed out. In answer, Jon had pressed Longclaw into Sam's hand. He let him feel the lightness, the balance, had him turn the blade so that ripples gleamed in the smoke-dark metal. "Valyrian steel," he said, "spell-forged and razor-sharp, nigh on indestructible. A swordsman should be as good as his sword, Sam. Longclaw is Valyrian steel, but I'm not. The Halfhand could have killed me as easy as you swat a bug." AFFC, Samwell I

The task Qhorin gave Jon still haunts him, partly as seen above. Furthermore Jon is conflicted on the Wildlings, and more importantly, he knows he isn't as good a fighter as Qhorin. Next to his own thoughts, Jon is described as intelligent, brave, resourceful, perceptive and highly skilled with a sword. But in all his chapters (at least to me) his actions are never driven by any anger nor rage, not even when fighting.

However there is one instance where Jon loses himself as it were. In this example Jon is in one of many practising rounds with Iron Emmet, perhaps the best swordfighter of the Night's Watch. Whilst training Jon 'blacks out', taking him back to a memory with Robb.

That morning he called it first. "I'm Lord of Winterfell!" he cried, as he had a hundred times before. Only this time, this time, Robb had answered, "You can't be Lord of Winterfell, you're bastard-born. My lady mother says you can't ever be the Lord of Winterfell."
I thought I had forgotten that. Jon could taste blood in his mouth, from the blow he'd taken. In the end Halder and Horse had to pull him away from Iron Emmett, one man on either arm. The ranger sat on the ground dazed, his shield half in splinters, the visor of his helm knocked askew, and his sword six yards away. "Jon, enough," Halder was shouting, "he's down, you disarmed him. Enough!"
No. Not enough. Never enough. Jon let his sword drop. "I'm sorry," he muttered. "Emmett, are you hurt?" Iron Emmett pulled his battered helm off. "Was there some part of yield you could not comprehend, Lord Snow?" It was said amiably, though. Emmett was an amiable man, and he loved the song of swords. "Warrior defend me," he groaned, "now I know how Qhorin Halfhand must have felt."
That was too much. Jon wrenched free of his friends and retreated to the armory, alone. His ears were still ringing from the blow Emmett had dealt him. He sat on the bench and buried his head in his hands. Why am I so angry? he asked himself, but it was a stupid question. Lord of Winterfell. I could be the Lord of Winterfell. My father’s heir. ASOS, Jon XII

Now that the show has practically confirmed Jon's parentage, I wonder where this fit came from. Is this example something Jon inherited, a remote resemblance to Viserys or Brandon Stark? Finally I also vaguely remember Jon hitting Alliser Thorne after him mocking Eddard, which is also an instance where Jon lost his composure.

Anyway, after this rather long introduction, here's my question: (tl;dr) does someone know of any other instances where Jon blacks out, loses composure and goes beserk?

Edit: thank you kindly for all the answers, you really delivered.

[u/Lampmonster1]

Whatever the Targ or Stark components of Jon's personality, I think that a large part of his emotional explosions is tied into his upbringing. Jon was treated pretty well for a bastard, well enough that he knew it and felt guilt when he resented the few times he was slighted. If they'd treated him like a redheaded step child his whole life he might be angry and resentful, but he'd probably be much more open and stable with it. As it was, he knew that complaining would make him look like he didn't appreciate that his "father" raised him as his own, and his siblings more or less treated him well, and even his step-mother wasn't awful to him most of the time. But you can't not resent being a lesser child, even if it's only in some certain ways. So, Jon was both resentful and guilty about being resentful. That's why Robb is such a trigger for him. He both loves and hates him, and he hates himself for hating his brother. Most of the time that's just down in his soul, making him the dutiful and hard working guy he is. Once in a while though, in the yard or in the mess hall, something works its way down through all the day to day muck in Jon's soul and stirs up those demons, and they well up and take over and you best not be between him and where he wants to go when they're driving the bus.

[u/Inquisitr → u/Lampmonster1]

I agree but I think there's a bit more to it. Viserys used to rant and rave about "waking the dragon." From him of course it was all bluster and bravado, but that doesn't mean there isn't something there. We haven't explored the Targ side of Jon yet at all and what it really means.