We all know dogs get excited when they see us, but is that because they miss us or know we're going to feed them? It's been speculated that dogs are pretty damn smart, but we need the science to back that up. So leave it to 60 Minutes' 2014 story about Chaser: the smartest dog in the world.
The part that surprised me the most is the lack of scientific research into the mental ability of dogs in general. To think that it's only been a few decades since work has been done with dogs is incredible.
If you want to see where your dog falls on the smart scale, you can check out the Dognition site mentioned in the piece.