As Bruce Schneier points out in his book Beyond Fear humans are very bad at assessing risk accurately. Ask yourself how scared are you of terrorist attacks vs. heart disease.

Notice how the government is putting much more money into the terrorist attack threat then the heart disease threat?

Here are some of the reasons why people are so bad and assessing risk: http://www.schneier.com/blog/archives/2012/08/five_neglects_...

(note finding the actual risk of death by heart disease vs terrorist attack is left to the reader...you might be surprised)