When people who don't know me to well decide to talk about politics, they often start by asking whether I'm conservative or liberal.  First I have to explain that I'm a libertarian, and then I usually have to explain what a libertarian is.  There are many ways to describe libertarians in a simple sentence.  One way would be to say that we believe first and foremost in individual liberty.  Another way is to say that we're socially liberal and fiscally conservative.  Sometimes I describe it as saying that our default position on any law is no.

That's not to say that we're obstructionists (though some would disagree).  That simply means that we need convincing every time you want to pass any law.  We'll agree to a law, but only after you make a good case for it, and show that the benefits outweigh any restrictions it places on individual rights.  Liberals and Conservatives don't have such a solid default.  They may default to no on some issues, but they'll say yes by default to others.  You then have to work hard to convince them of no, if that's possible at all.

Having a default position of no may seem like a minor difference, but I assure you it is very important.  The amount of work required to switch someone from one position to another is significant.  Frankly I'd rather have make sure that its always harder to say yes, than say no.  It's just a good common sense default position.