For Gamal Hassanein, it began with a slap.
The unemployed 24-year-old was arguing with a police officer when the man struck him across the face _ a blow that seemed to sting for months.
"He stole my dignity with that slap," said Hassanein, who does odd jobs to make money. "We could never stand up to those officers before because we were afraid. But we're no longer willing to be silenced by our fear."
The tens of thousands of protesters who have thrown Egypt's 30-year-old regime into tumult come from all walks of life _ conservative Muslims and Christians, yuppies and the unemployed, young and old. For many, the protests demanding that President Hosni Mubarak step down were a catalyst for years or decades of repressed anger at mistreatment at the hands of the state.
One after another, they describe a moment buried in their memory that came gushing to the surface as they saw others taking to the streets.
Hossam, a 23-year-old Cairo resident from the upper-middle-class Maadi neighborhood, said he thought of his cousin, who drowned seven years ago after falling out of a pedal-boat on the coast. Emergency services did not respond to a call for rescue after learning that the victim was not a Western, said Hossam, who declined to provide his last name for fear of official retaliation.
"Why are we treated like this?" he asked. "We will get rid of this regime."
The personal humiliations are exacerbated by a sense of national shame at a series of failures that throw into relief Egypt's slide from cultural and political trendsetter of the Arab world to a country besieged by poverty, illiteracy, corruption and official incompetence.
A ship sinking in the Red Sea left more than 1,000 dead. The national football team lost a World Cup game to Algeria. The government has failed to reconcile warring Palestinian factions, and appears unable to influence Israel's actions in the Middle East.
For years, though, the anger had no outlet.
Egypt's traditional opposition groups _ socialists, liberals and Arab nationalists _ have been marginalized by Mubarak's years of restricting their freedom while buying their cooperation with parliament seats and other patronage.
The largest and most organized opposition group, the banned Muslim Brotherhood, has not reached out to non-conservative Muslims, limiting its base of supporters.
The return of Nobel Prize laureate Mohamed ElBaradei to Egypt in February 2010 energized many young Egyptians, who called on him to run as president. But his appeal was limited by his image as a secular expatriate.
Then, in June, the death of 28-year-old businessman Khaled Said at the hands of undercover police set off months of small protests that swelled into mass outrage after demonstrators grew emboldened by Tunisians' overthrow this month of their longtime autocratic president.
"It is a process brewing for several years," said Hossam al-Hamalawi, a 33-year old blogger. "Activists from small groups have been agitating for these days of anger ... but no one can claim it."
Mahmoud Elhetta, who leads a campaign supporting ElBaradei for president, said his group of 1,500 activists had been training for organizing civil disobedience and large protests.
"We each had our tools and we were waiting for this moment," Elhetta said.
Women dressed in black all-engulfing veils and wide flowing black robes followed other with expensive hairstyles, tight jeans and name-brand sunglasses.
"The people want to change the regime!" they shouted, a staccato Arabic chant that first appeared in Tunisian protests.
Aya Barada, a 25-year-old legal consultant wearing a blue headscarf and tight jeans, said she learned about the protests from Facebook, and relentless campaigning by activists who used Said's death as a rallying cry against the government.
"I am making good money. I personally am not suffering. But the conditions in Egypt are ... bad for me, my family, and ultimately my country."
Homemaker Sadat Abdel Salam wore a black abaya, or robe, and a face-covering veil to the protest.
"They are taking us lightly and they don't feel our frustration," she said. "This is a uprising of the people and we will not shut up again."
Tarek el-Tablawy and Hadeel al-Shalchi contributed to this report
For Gamal Hassanein, it began with a slap.