The word "cynicism" is used in at least two senses, and these are related, but the distinction between them is quite important.

Normally, when we label a person a cynic, we mean that they regard everything as bullshit - or at least that they want to be seen that way.  But, historically, the word derives from a school of philosophy, tracing its lineage back to Socrates, and ultimately giving birth to Stoicism.  These philosophical Cynics were, it is true, extremely fond of identifying all those aspects of life that fall into the bullshit bin, and yet, implicitly, they did hold Nature (physis) as the standard of anti-bullshit, against which everything else was measured, and, verily, found to be bullshit.

These worthies have a controversial geneology, but the figure who appears most consistently as the archetypal Cynic is Diogenes of Sinope.  Quite probably, the majority of stories we have about him are mythic - but what a myth!  He famously is said to have wandered in broad daylight with a lit lantern, rushing up to each person he encountered and staring intently into their faces, then moving on with an air of disappointment.  Questioned, he explained that he was looking for an honest man. 

It was once said of him:  "That man is Socrates gone mad."  As if that were a bad  thing! 

This Diogenes - sometimes also counted as the first Discordian (though the Cynics revered Heracles rather than Eris) - lived outdoors, possibly in an amphora, or large clay jug.  It is said that when his reputation as a philosopher had spread, Alexander the Great, in a mood to patronize the humanities, went to visit Diogenes at his campsite, where he was sunning himself.  You must understand that from a Greek perspective, Alex was the ruler of the world - or at least, as much of the world as anyone knew about.   So, the Ruler of Everything offers our man Diogenes a boon - what would the eminent sage like?  Diogenes replies:  "Step to one side; you're blocking my light."  Why?  Because Alex was just a man, after all, and Diogenes had all he wanted already.  From the perspective of Nature, a man's a man, for all that, and nothing other.

Diogenes' father had been implicated in a counterfieting scandal (or something like it).  Now, in an honor-oriented society like that of the Hellenes, the shame of a criminal father was a burden most would not easily bear.  Diogenes took as his personal motto: "Deface the coinage!" which remains good advice.  What is a coin, after all, but a hunk of metal?  The imprint on it, and its presumed value, are simply matters of culture (nomos) and the unease we may feel at the thought of drawing Groucho glasses on Geo: Washington's face is simply a superstition arising from our inability to see that culture is - bullshit.  Once the coinage is defaced, it reveals its true, natural character.

When Diogenes saw a boy drinking from a river by scooping the water up with his hands, he instantly smashed his drinking-cup on the ground, bemoaning what a fool he had been, all his years.  He had seen the difference between the actual nature of water, and the cultural construct of drinking. 

And as with this, so with everything.