8 is pretty much the robot of the Enneagram. 8 anger literally feels like a solid wall moving towards you. If an 8 is on your tail, he won't make you feel scared, he'll just coerce you into complying in the quickest, most pragmatic way possible.
If someone's mistyped as an 8, they're probably a 3. 3 anger is much more personal, much less predictable, and much less scary. 3s will periodically release their anger in eruptions, and they'll only stop if you either 1) tell them what they want to hear, or 2) get them so angry that they disgrace themselves and soil their own image in front of their loyalest followers, forcing them to retreat and rebuild their damaged facade.
3 has no tolerance for lack of ambition. They're naturally proactive and they want you to be proactive. When they "explode," they often attribute their anger to other people falling short of their visions.
8 values constancy and productivity. If an 8 is your boss and you don't fulfill one of their commands, they get "mad" at you to force you to obey -- the anger is very mechanical and impersonal. If you're doing everything they say and following the rules, they'll completely leave you alone and possibly ignore you. 8 does not expect you to go above and beyond, only to meet your quota.
8 doesn't have a sense of honor in the same way 3 does. 3 drastically regulates its behavior to appear socially acceptable. 8 abides by the laws of external structures and systems -- if you had seemingly unlimited power, the fastest way to graduate upwards to authority is by joining the authority.
One weird thing I noticed about 8s is that they look very good in a photograph. They have a very pleasant smile, almost looking better than other types.
A 3 in a photograph will often look either very over-the-top, or very calculated in his appearance.
8 has no desire for fame, recognition, or the spotlight. They only want to be able to keep doing what they've been doing, and if you're incompetence is hindering them specifically, they'll target you. They'll shoot you down quickly and cleanly, and you'll probably forget it happened.
3's fundamental desire is to be presentable. Often, this means fame and recognition. Other times, it means keeping quiet like a good citizen should do.
8s tend to have more variety in their friendships. If you know an 8 who isn't in a position of authority over you, you're a half-decent person, and you're not causing any particular social trouble, an 8 may casually befriend you. They'll show affection when it's appropriate, but they're the most likely to spend more time on their work and less with other people.
3s may often behave very aristocratically and reject certain people who fall outside of their class and/or criteria for what's appropriate. 8's criteria is a bit more lenient and focuses considerably less on appearance, but all on the "function" of the person and how they behave in the social "system."