I'd say that there seem to be seven major misconceptions that most modern folks have about the Roman Empire:
Romans were bad people. After all, they crucified Kirk Douglas. And Jesus. They threw criminals to the lions. Their soldiers wore tiny little skirts, and they spoke a pretentious language that makes everything sound like a diploma or state motto.
This seems to be the most common misconception with most folks. most folks seem to consider the comparison an insult. Well, two hundred years ago, the Romans had a better reputation. The framers of the American constitution loved the Romans. They built their government buildings to look Roman. They named the principle lawmaking body "the Senate" after the Romans. They chose the eagle as their national symbol. They even called their new system of government a republic, using a Roman word instead of an English word like commonwealth or a Greek word like democracy. Why if Thomas Jefferson could hear us calling America the New Rome, he would dance a happy dance and hug every columnist who made the comparison.
The Roman Empire was ruled by an Emperor.
In the intervening 2000 years, we've taken to using anglicized/russified/germanized variation of Roman terms like Emperor, Czar and Kaiser to label absolute rulers of vast territories, wielding godlike powers that pass with dynastic regularity from father to son across the centuries, but this represents a kind of semantic drift. The original meaning of the Latin word imperator was probably closer to the modern generalissimo.
If the classical Roman Empire were planted in the modern world, we probably wouldn't call it a monarchy. It was more of a military dictatorship, and we'd call the emperor a strongman, a person who pulled all the strings, but didn't necessarily hold any fixed constitutional office or have any kind of title beyond
primus princeps - first citizen.
There wasn't any kind of established rule as to who became emperor after the old one died. Generally, the role fell to a close associate or adult relative with combat experience and influential connections. Almost as often, the office was grabbed by coup d'etat. It wasn't until the accession of Commodus, son of Marcus Aurelius, that Rome got its first emperor born to the purple, that is, born to a father who was already emperor. That was in 180 AD, or 211 years after Augustus.
The Romans sucked their conquests dry through crippling taxation.
The Empire lasted as long as it did because the Romans weren't idiots. When the governor of Egypt sent Tiberius more taxes than he was supposed to, Tiberius reminded him: "I want my sheep shorn, not skinned."
The Roman Empire deliberately conquered everything in sight.
Actually, it was the ambitious, glory-seeking politicians of the Republic that did most of the conquering. The Emperors generally tried to keep the frontiers as quiet as possible.
Alright then, the Roman Republic deliberately conquered everything in sight.
Actually, the Romans often tried their best not to conquer their neighbors. They would have preferred leaving independent client states under puppets. Generally, the Romans fought three wars with every country around the Mediterranean. The first war was a warning not to mess with Rome; the second was a reminder that Rome won the last fight, so mind your manners; and the third war resulted in an exasperated Rome taking direct control of a troublesome client state.
Roman procurators enforced the law throughout the Empire.
Because we draw maps of the ancient world with the Empire shaded all one color, we sometimes forget the complexity of the Roman government. It's only a slight exaggeration to say that each province had a unique relationship to the central government. Peaceful provinces were ruled by the Senate. Provinces that were under martial law because of rebellion or proximity to the frontier were ruled by the emperor. Some Roman lands were ruled by client kings like Herod and Cleopatra. Many tribes and city-states remained under self rule, and would probably have considered themselves independent allies -- certainly not conquered vassals. (By way of comparison, the diplomatic community of today counts Kuwait and South Korea as independent countries, but they only exist because the US keeps troops planted there. Is that independent?)
Rome fell.
Yeah, after about a thousand years. Woohoo! ROMA! ROMA! ROMA!
Sorry couldn'r resist.
The point I should be making is that it's a mistake to cram the thousand year rise and fall of the Roman Empire into the small history we know in our own lives. Rome wasn't built in a day. You can quote me on that.
One final nitpick. Most folks like to think of Carthage as the 'heroes' of the Punic wars while ignoring items like Hannibal sacrificed his youngest son on the sacrificial altar of the god Baal. While the Romans tried their damnedest to wipe out human sacrifice, which they found heinous.
After whipping the Carthaginians at the battle of Zama in 202 BCE, the days when enemies like Hannibal would threaten the homeland and march to the gates of the city had finally ended. Carthage, the only expanding rival in the Mediterranean world, had been knocked out of the fight and shorn of its empire, but it was mercifully left alive as a nation.
At the end of the Second Punic War, the Romans could proudly and plausibly deny imperial ambitions. Although they had beaten the other peoples of Italy over the course of several previous generations, the Romans had allowed them to retain self-government in exchange for military alliances that put Roman garrisons up and down the peninsula. The Romans hadn't even picked a fight with Carthage this time around. They had honorably gone to war to protect the tiny Greek city-state of Saguntum from the Carthaginian aggressors. The time when Carthage would be sacked by Roman legions without provocation, its people massacred or sold, its land plowed with salt, was still half a century in the future.
Cheers, Thorgrimm