Hassanein Badrie, a 49-year-old accountant, already had waited for more than two and a half hours to vote on a proposed national constitution, and still had at least half an hour more to go.
But the neatly-dressed man looked as alert and content as when he joined the end of the lineup that snaked its way back and forth on the sidewalk and out onto the road, around a parked bulldozer before entering the local public school where people cast their ballots.
"It's definitely worth it," he said. "This is democracy and we waited a long time for it. The future of our children is at stake."
His 10-year-old son, Mohammed, wasn't quite so enthusiastic, holding onto his father's hand and resting his head on Dad's well-pressed vest.
"I'm very excited about this constitution," Mr. Badrie explained. "It will bring stability to the country."
A divided Egyptian nation began voting Saturday on a controversial, hastily drafted constitution promoted by President Mohammed Morsi and the Muslim Brotherhood organization from which he hails.
With his popular support plummeting, Mr. Morsi needs all the help he can muster from the country's religious extremes if that constitution is to pass. The result of it all could be a regime that is much closer to the rigid Salafist style of Islam.
Sporting a neatly-trimmed beard, Mr. Badrie had the look of a supporter of the Muslim Brotherhood, the organization whose political representatives drafted the constitution.
But Mr. Badrie said only that he is a religious man.
"I'm a religious Muslim too," said Hussein Abdel Aziz, a 41-year-old engineer, standing behind the Badries. "And I'm voting no."
"This constitution doesn't have any guarantees about health care or work," he explained. "We need that."
Egypt's economy has been hard hit since the initial euphoria over the ouster of former president Hosni Mubarak last year. Continued protests and sometimes deadly clashes have driven away tourists and foreign investors.
Places such as Ein Shams, this teeming, mostly poor working class neighbourhood have been especially affected. Some don't have the money to put decent food on the table, and would accept any solution that would let them get back to work.
But a surprising number are skittish about the direction Egypt may take with this constitution, perceiving it as an open invitation for Islamists to take full control of the country.
Though a Muslim himself, Mr. Abdel Aziz is one of those concerned. "The constitution must provide for everyone," he said. "It's worth starting over to make sure that happens," he said, despite the long delay that would have.
"Two weeks ago, I'd never have imagined that so many people would come out to vote against this constitution," said Hisham Kassem, a former newspaper publisher and human rights advocate.
"There's no political organization such as the Brotherhood has on the 'yes' side, but they're coming out of the woodwork and marching to the polls like it's some kind of science fiction movie in which the people have been brainwashed."
The clogged streets in Ein Shams, Heliopolis and the mixed neighbourhood of Shubra certainly testify to this.
The outcome of the referendum may be much closer than most people thought.