Be warned: this article deals primarily with shark attacks, the lottery, beer, and how to get a date using math. Is it a good decision to keep reading? Unfortunately, the answer is "you need to keep reading to find out."
Sound irrational? Good—your massively irrational mind should have no problem with it, then.
Consider this: every year when the Discovery Channel broadcasts "Shark Week" visits to Florida beaches decline. Presumably, the network's programming makes the waters no less safe (assuming sharks are not, in fact, empowered by cable television). However, after watching a week of kicking legs seen from below, the idea of shark attack is refreshed in our minds and we choose not to offer ourselves as bait.
This phenomenon is known as an availability heuristic — a heuristic being a rule-of-thumb. Our rationality is subverted by easily available sensationalist images.