WHY IT'S COOL?
It's a very clever twist on the 'dog ate the keys' trope. The dog is perfectly cast-and yes, that's important. The actor does a marvelous job of conveying 'not again'. There's not a wasted shot. But...
WHY WE LOVE IT?
The music. The song choice MAKES this spot. Although sadly, Johnny Cash has ironically become one of the best artists to sell your product with his music.
WHAT CAN YOU LEARN FROM IT?
Don't forget the music! Yes, commercials are a visual medium, but sound & music should always, ALWAYS, get equal attention. We can't repeat that enough! Music and score is what we use to set the mood for our visual storytelling in commercials, TV, and film. In this case, the song choice sets the mood brilliantly: waxing nostalgia and tongue-in-cheek humor in one blow. We all know a dog or had a dog that was a lovable nuisance.
You might not have the budget for a Johnny Cash song, but there is an amazing amount of music available via sites like Premium Beat andThe Music Bed. And don't forget your local artists who may be willing to grant the rights to their work if you're going to get it on TV or use promoted ads on the web. The point is, don't skip over the music. Take the time to find the song that sets your ad's mood.