I reached that point last week, watching Kamala Harris’ acceptance speech at the Democratic National Convention, and what I yelled at the screen was "the enemy is us!".
She had got to the foreign policy sound-bite and was talking about the "enduring struggle between democracy and tyranny" and Donald Trump’s desire to cosy up to "tyrants and dictators".
That’s when I lost it.
I’m not denying that such a struggle exists, but we’re looking at it through the wrong lens.
The democracies are generally (though not always) less wicked than the tyrannies, but the real struggle is far older and much deeper than most people realise.
Human beings are primates, and our original social structure was almost certainly like that of our close evolutionary relatives such as chimpanzees.
Our ancestors would have lived in small groups of 30 to 100 individuals, each ruled over by a violent, despotic "monkey king".
There would have been a constant struggle between the adult males to seize the top spot, complete with alliances and betrayals, but nothing ever really changed. "Meet the new boss. Same as the old boss", as Pete Townshend once put it.
To see this in action, watch a brilliant Netflix mini-series called Chimp Empire.
But our distant ancestors broke that ancient pattern. They were more intelligent than other primates, and they could see that the perpetual struggle for power wasn’t worth it.
Any individual’s chance of winning the top job was very small, and the fate of the rest was to be bullied and beaten all their lives.
They also had language, probably for at least the last 50,000 years and maybe much longer. So they could imagine a better kind of future in detail, and they could plot and make alliances to create that future.
At some point in our very distant past, there was a revolution.
Maybe it happened spontaneously in a thousand different bands, or maybe it only happened once and then the example spread like wildfire, but most of the adult males banded together, overthrew the reigning boss — and adopted a new rule, rigorously enforced, of absolute equality.
How do we know this? Because that was the rule in every single hunter-gatherer group that the anthropologists encountered in the middle decades of the last century, when the first generation of anthropologists studied the social structure of the last generation of hunter-gatherers who had had no contact with mass societies.
They were so strenuously egalitarian that they would "cut down the tall poppies": men giving themselves airs or claiming privileges would be first mocked, then ostracised if necessary, and in extreme cases driven out of the band or killed.
There were charismatic individuals who could persuade others to their point of view, and great warriors who would be given temporary leadership roles in the chronic inter-band warfare, but the worst social crime was for one man to give an order to another.
Women’s positions varied from one hunter-gatherer culture to another but were certainly better than in the mass societies that eventually destroyed them.
And it all lasted long enough — at least tens of thousands of years — to make equality and freedom default human values.
So what went wrong? Mass civilisation happened.
Societies of millions of people were far richer and more powerful than tiny hunter-gatherer bands, but it was impossible to run them by discussion and debate among equals.
The new, crop-growing mass societies had to be tyrannies, and they were so numerous and powerful that they drove the old, egalitarian values underground.
However, those values never actually died. Rebellions were constant, but always crushed.
Ten thousand years of tyranny and oppression — and then early mass communications (just literacy, books and pamphlets) finally made it possible for large numbers of people to make decisions together as equals.
That opened the door to the American Revolution circa 1776, the French Revolution circa 1789, and two more centuries of struggle to recover our old egalitarian values and rights.
About a third of the world’s people now live in countries where everybody really has equal rights before the law, and the other two-thirds live in countries that pretend to be like that.
So why did I yell "the enemy is us"?
It comes from a long-dead American newspaper comic-strip called Pogo, in which the main character, a humble opossum, deliberately misquoted an American military hero of the War of 1812 who once famously declared his victory by saying: "we have met the enemy and they are ours".
No, Pogo said. It should be "we have met the enemy, and he is us". It is two contradictory human heritages at war, and the right one is winning.
Understand the context, and the world will start to make sense.
• Gwynne Dyer is an independent London journalist.
