> 
> Being too American, or American at all, is pretty much the worst thing
>  a Brit can be. “American” is synonymous with pushiness, tactlessness,
>  and **puppy-dog earnestness**.
> 
> 
> *The Geography of Bliss by Eric Weiner*
> 
> 
> 

What is the meaning of '**puppy-dog earnestness**'?