High electricity bills were the trigger for the protests, but the real reason was the disappointment of the people at the lack of economic progress.
"Thieves, robbers, mafia" - these have been the kinds of accusations which have been chanted by thousands of demonstrators in Bulgaria over the last few days. Initially it was because they thought their electricity and heating bills were too high. But they soon turned against the government in general.
In fact, electricity in Bulgaria is the cheapest in the European Union - Germans pay three times as much. But the two private electricity supply companies, the Czech CEZ and the Austrian EVN, are demanding very high network charges so that prices have doubled in a year and many people can't afford them any more.
With an average income of just 360 euros ($480) a month, or pensions of 150 euros, the new high prices meant that, when winter came, many Bulgarians felt themselves forced into poverty - even though the government had imposed a maximum price for power. But the electricity companies ignored that and have been charging more, saying that they would otherwise not be financially viable.
In addition, the decrepit Bulgarian electricity grid loses about 25 percent of its power - about three times as much as the EU average - and that has to be accounted for in the price too.
Poverty in Bulgaria
The government led by Boiko Borisov came to power in 2009 after the first elections following Bulgaria's accession to the EU in 2007. It's also the first government in 16 years which has resigned early.
According to Marco Arndt, head of the Konrad Adenauer Foundation's office in Sofia, the electricity price was only the catalyst for the protests and the government crisis. The real reason was the disappointment felt by many Bulgarians that their hopes of a speedy increase in their prosperity have not been fulfilled. Bulgaria is, together with Romania, the poorest country in the EU - but it's also one of the most financially stable. It fulfils the so-called Maastricht criteria, which is quite an achievement, bearing in mind that it borders directly on crisis-ridden Greece.
"But the financial stability has come at a high cost," says Arndt. "There's been virtually no investment in infrastructure, and, where it has taken place, it's been largely financed by the EU structural fund."
Income is still very low and pensions are scarcely enough to live on. "According to figures from the Bulgarian business newspaper in February, 1.5 million people live below the poverty line - that's a fifth of the population," notes Arndt.
Johanna Deimel, deputy head of the South East Europe Society in Munich, agrees that the electricity price is only the trigger; the real problems stem from the damaging economic and social policies of the government.
"This is a valve to allow protest against social injustice," she argues. "The poor social and economic situation of large parts of the population is only partly due to the economic and financial crisis in the eurozone. So the demonstrators are right to direct their protests against the government."
Deimel considers the resignation of the prime minister and the government to be highly irresponsible and dangerous. "A man like Borissov, who has always nurtured his image as a mover and shaker, throws in the towel like a small child as soon as the people are annoyed with him and go out on to the streets in peaceful protest," she says.
The violent escalation of the protests has put the land into a very critical situation: "It needs above all a level-headed and clear leadership," says Deimel, "not a sulky resignation."
The hour of the populists and the extremists
Borisov is seen both at home and abroad as a pro-EU populist who claims to only be listening to the people. He explained his resignation on Wednesday (20.02.2013) by saying that when "his" police used violence against the people, as they did in Sofia on Tuesday, that was something he could no longer accept.
In reality, it's more likely to be about holding on to power. Observers believe he wants elections as soon as possible since support for his GERB party is falling rapidly and there's a good chance that he would lose his majority if he waited until the regular election date on July 7.
Deimel prophecies hard times ahead: "I fear the election campaign will be very dirty." She doesn't believe GERB has much of a chance, "but it's the hour of the populists and the extremists - the center ground will have a difficult time."
Now it's up to the president, Rossen Plevneliev. He could call for talks to set up an interim government. But observers say that's unlikely: he was once a minister in Borisov's government, and he's likely to listen to his ex-boss and call the early elections Borisov wants.