You receive an email containing interesting news.
It ends with, "Learn more. Visit our website. Link below."
The link is an attachment named, "OurGreatSite.com".
You're interested. You click it.
BOOOOOOOOOOOOMMMMMMMM
Oooops!
You forgot that ".com" is also an old MS-DOS executable file extension. Some .com's mean business. Other .com's mean monkey business.
Thank goodness you updated your virus protection recently.
You did, didn't you?