I'll have to say SOMETHING he's so American and thorough, he'll insist upon having a reason.
The speaker considers Americans to be thorough and insistent.
They don't have to say anything, the American is lazy and won't ask for any reasoning.
Two people play music.
Poirot is not interested in the quarrel.
The people are running towards the building
A picture of Burning Man.
Walking around LA's open-air markets is waste of time.
It is completely impossible.