I may be making an American Cultural Assumption here. I'm mainly thinking of United States politics. In your country, the more common terms might be Left and Right, where extreme left = communism and extreme right = fascism. (A strange choice of endpoints for a continuum, if you ask me.) In the United States around the time of the end of the Soviet Union, liberal journalists began referring to communists as "right-wing", apparently to express disapproval, making the terminology even knottier than usual.

Adding further to the confusion is the fact that most conservatives in the United States today also call themselves "classical liberals": that is, exponents of Lockean enlightenment values such as reason, liberty, and free trade.

In the United States, the Democratic Party is generally considered liberal (or left-wing), and the Republican Party is generally considered conservative (or right-wing).

Liberals care about the common people, while conservatives care only about rich people.

I was told this as a child. As an adult, I realized that it was told to me by a liberal, and is a rather biased characterization.

Liberals favor change, while conservatives favor the status quo.

A characterization with strong etymological backing. After all, conservative means "tending to conserve." However, when the elder George Bush ran for re-election, he said that he offered the American people "change". Something about the Democratic Party having controlled the government for an awfully long time. Many conservatives argue vociferously against the status quo. But there is probably a core of truth in this one. See the next attempt.

Liberals worry about the abuse of power, while conservatives worry about the loss of traditional values.

Here the distinction is the type of fear that motivates people to get interested in politics. Liberals worry about the rich mistreating the poor, wealthy capitalists mistreating the environment, majorities mistreating minorities, bosses mistreating employees, unelected officials applying the law unfairly, etc. Conservatives worry about all manner of traditional concerns: foreign enemies, financial insolvency, bad manners among the youth, crime, the decline of traditional values, rituals, and religion, etc.

Interestingly, neither takes the other side's fears very seriously. Thus the fears are what the respective parties believe are not merely bad things, but likely bad things--likely enough to justify worrying about and even legislating about.

Something that I like about this definition, and that I think suggests that it's on to something, is how it frees you from any loyalty toward one or the other. You can stand back and think, "Hmm, is abuse of power more of a problem here, or practical difficulties such as financial solvency or shared understanding of publicly acceptable behavior?"

Liberals believe in the perfectibility of man, while conservatives believe that man is incorrigibly imperfect.

Heard from an arch-conservative, Robert Bork (not in these exact words, but close). Thus liberals strive to create perfect systems of government with perfect laws. Communism is an extreme form, attempting a perfectly equitable distribution of wealth. Many liberals ("pacifists") want to do away with war entirely, even through unilateral disarmament. Conservatives, on this view, are more realistic, working within existing legal frameworks, recognizing that creating perfection is beyond human wisdom, making do with capitalism, etc. Conservatives would certainly like to do away with war, but believe that it's impossible, and consequently believe in continual preparedness for war.

There is no fundamental distinction. Liberals and conservatives choose their views simply to have opposing views, usually in some vague but unsuccessful attempt to create a common denominator that does not exist.

Evidence for this one is the numerous issues on which liberals and conservatives have reversed themselves, always 180º out of sync with each other. For example, in the United States before World War II, conservatives wanted to stay out of foreign wars. Liberals branded them "isolationists"--naïve fools who thought their country was an island insulated from the rest of the world. In the 1960s, the conservatives wanted to get involved in foreign wars in order to contain communism. Liberals branded them "paranoid"--naïve fools who believed childish scare stories and who were going to risk nuclear war because of bogeymen. Conservatives branded liberals "naïve"--unaware that there is evil in the world and that it thrives mainly when good people stand idly by. More recently, liberals have been wanting to straighten out lots of other countries' squabbles, such as in the Balkans. The conservatives are becoming "isolationists" again, and the cycle continues.

Thus there is no common denominator, just an attempt to define positions in order to say, "We're not you, and thank goodness for that." Liberal and conservative are thus arbitrary tribes, something like fans of football teams.

A rather disturbing hypothesis. If true, people have been taking sides and pointing fingers at opposing sides for a very long time now, not over any substantive issue, but just because people like taking sides and pointing fingers.

Further evidence for this one is the fact that no one seems to agree on what is the difference between liberal and conservative. The existence of this very page is evidence that this hypothesis is true.

There are distinctions, but they are more about a general approach and are not always identifiable in single issues. Also, liberals and conservatives take opposing views partly because they both believe in being a Loyal Opposition

The above point is very interesting and is well put. However the distinction should not be over a single issue, but be about more general concepts. Conservatives tend to prefer established values, and tend to put an emphasis on Law and Order, on social values and structure and on wealth creation. However, they do not ignore more liberal values such as individual freedom, social welfare and public provision of many major items eg education. Liberals might tend to see the emphasis the other way around.

So US Conservatives before WWII wanted to stay out of foreign wars because US interests (ie US wealth creation) were not affected, or not in a way that could be usefully addressed through war. In the 60's Communism was seen as likely to affect the American Way of Life (and US economic interests in Asia, which were increasingly important), so Conservatives wanted intervention. Both reactions were consistent with a Conservative worldview.

What they both, in democracies, believe in is that there should be a Loyal Opposition. Taking the opposite view to the current government is important both for electoral reasons but also to ensure that there is a proper debate about all the issues on a given topic. Proper debate gives better and more moderate implementation of policies.