There's been a theory going about for a long time about how Donald suffers from severe Post Traumatic Stress Disorder, mostly because he's so easily provokable, overly vigilant, and has wears a sailor's uniform all the time. That's a logical assumption to make, but it has deeper canonical support than that.
In the early cartoons, Donald was a bit explosive, but, probably due to comic regulations back then, (where in a love scene so much as a phone left at the table without being hung back up was too suggestive of sex to be published,) not nearly as vicious as he is sometimes today. Donald was also never in the navy, even though he dresses like a sailor. In the various propaganda cartoons that were made by Disney in WWII, he was a paratrooper and a commando, meaning he probably saw some pretty tense shit out there fighting the Nazis and the Japanese. At one point he was a prisoner of war, Which brings us to the cartoon "The Furher's Face" in which he has a bad dream about being forced to live the life of a person in Nazi-controlled regions.
Hell, he has a lot of nightmares, even in modern cartoons, and some are particuarly shown in this cartoon featuring him trying to murder his nephews:

Yeah, he's also violent. Notice how in the Pre-WWII media, he always tried to trap or catch Chip and Dale, where in much of the later things, he tries to outright kill them. He also has trouble talking about it. After the WWII era, I've never seen him say anything about war in general, let alone his own service. It's rather odd, really. And, as many people with severe and un-treated PTSD have, he has significant problems with work, family, relationships, he's even violently threatened some of his best friends.
Of course, this could all just be because violent tempers are funny and often used in cartoons, but with Donald's WWII history, it really makes me think.