Democracy is a political system through which the majority of the population rules. It differs from other forms of dictatorship by the size of the ruling class. It is believed that democracy leads to freedom, peace, and prosperity. This is not the case. Democracy is potentially the most dangerous of the political systems.
Democracy is rule by the majority. There are no limits to what the majority is allowed to decide. It can decide laws based on whim, with no respect for rights It can pass laws against painting your house white as easy as it can pass laws against murder. There is no guarantee of a just democracy.
There is one distinction between a democracy and many other forms of dictatorship. A minority dictatorship must fear the majority. If they oppress the people too much, the people will rebel. No dictatorship can stand against the full will of the people.
Those that are ruled think in terms of justice. Those that rule think in terms of power. When the majority rules, they stop thinking in terms of right and wrong. They're claim to power is "the will of the people". Wherever that power leads, they follow obediently. If slavery is the price of power, they take it willingly.
Those that suffer the most under a democracy are the minorities. The smaller the group, the less say they have in policy. But majority and minority change with each issue or policy. Everyone finds themselves as part of the minority at some point. But since the majority rule, the government has no fear of rebellion to circumscribe their actions.
That being said, voting is a very useful tool in constructing a proper government. Unlimited democracy is a bad thing in itself, but a constitutional representative republic in which the people elect representatives to govern according to a rights-respecting constitution is the best form of government so far discovered.
There is a disturbing tendency for people to equate a democratic government with a just or proper government. They will say that one government is bad because it's not democratic and another is good because it is, and we must bring democracy to the world! What constitutes a proper government is the preservation of rights, not the method by which that preservation is brought about.