Last week I was driving through the mountains of North Georgia when I passed an aging, hand-painted sign along the road in front of a farm.

“Land values in this area are increasing 20% annually!” said the sign, which then provided a phone number to call for information on how get in on this golden opportunity.

About two miles later I passed another farm with another sign – this one larger, fresher and professionally lettered.

“Farm for sale: 57 acres,” said the sign. “Reduced 50% from original asking price.”

I couldn’t help but laugh at the irony. The story of an epic asset bubble, told in a couple of farm signs two miles apart.

Bubbles are like that, aren’t they? Always so obvious, but only in retrospect.

Every third piece of mail I received in 2006 was a pre-approved credit card or checks for a home equity line I never asked for. I applied for a mortgage in 2007 and when I tried to provide income verification the mortgage broker told me he didn’t need it because it would just “gum up” the underwriting process.

I look back on those days and shake my head, amazed and appalled at the way so many different entities and institutions conspired to create a massive real estate bubble that took the whole economy – and very nearly the whole financial system – with it when it popped. But I only see it now. I didn’t see it then, in real time.

We think we know, but we don’t. In fact, what we think we know is often dead wrong. A year ago oil prices were sitting at almost $150 a barrel, and commodities from wheat to copper to grain were soaring in price. A commodities fund seemed like a no-brainer. And then, out of nowhere, commodities prices suddenly plunged, a harbinger of things to come in the economy.

We think we know, but we don’t.

It is an innate part of human nature that we are massively influenced by the current environment we are in, and by the mass media that reports it to us all day, every day. This is why a disciplined investment strategy is a must – one that is based on long-term fundamentals, and is never, ever altered based on short-term market conditions. That is the one, sure way to navigate through the manic/panic dynamic that is inherent to all bubble events.

It’s how we avoid getting caught up in the group think that plagues investors in every day and age.

It’s how we avoid having to hold a half-off sale for our farm that was increasing in value at a 20% yearly clip when we bought it.