Cool is not just an object, but the story behind it.
Cool is inherited shotgun with a worn stock that fed a previous generation during hard times.
Cool is the gun a veteran built based on his service rifle. It's a reminder of his or her service and a tool for teaching the next generation.
Cool is a work of art in motion by a good custom builder.
Cool is a pistol with the wear of years in the holster and thousands of rounds fired in practice. The finish is worn on the holster contact points, the top of the chamber is shiny from the slide moving over it tens of thousands of times, and when the owners hand picks it up it points effortlessly as all that wear is translated into proficiency.
My coolest gun is the G34 I bought as an IDPA gun, after I replaced the sights, did a trigger job, stippled the grip, carved my initials into the side, and started shooting the heck out of it. It captures my essence more than any other gun I own, and that would be pretty cool to anyone who thought I was cool.
My second coolest gun is an HK P2000. I haven't shot it for a long time, but for years it served as a CCW without a failure, and it has the wear to show for it.
Shiny + overpriced = a lot of things. Automatically being cool is not one of them.