My 13 week old little guy goes absolutely crazy when he sees and interacts with other dogs. He's mostly fine with humans (he tries to jump up, but is fairly good about not biting).
He will bark non-stop at the other dog (30+ minutes straight if you let him) and repeatedly tries to jump on top of them, bite them, and chases them everywhere.
He never "settles down" and will continue to antagonize the other dogs. Even if the other dog tries to put him in his place, he will keep going. One of my relative's full-grown, 25 lb dog is afraid of him!
Just got him enrolled in puppy classes, but is this normal behavior? He seems to be incredibly excited rather than aggressive, but he's so tenacious around other dogs and never settles down, so it's a little worrisome.