There is a lot more to this silly phenomenon than meets the eye.
After the War of Independance, Americans did their best to shun the British and their influence. They went so far as to change the side of the road on which people drove ..... just so they were not following British custom! Ridiculous? I think so.
So, there was a deliberate "exclusiveness" which can still be seen reflected in American people's use of the English language. The overabundance of strange, bizzare and baffling idioms used by Americans is another good example of this clique mentality.
I don't mean to be seen as being 'dark on' (critical of) Americans, but isn't it time they joined the 'World English Club' and stopped wandering off on some weird tangent?
While they are at it, why in blazes don't they cease being the only nation that still uses the Imperial measurement system (they seem to have overlooked the fact that the British introduced it), and start using the metric system like the rest of the world?
And for crikeys sakes .... why did they butcher Gods game of cricket? That thing they do called BasXXrdball just aint natural!
P.S. love their V8 engines and their really big guns though
P.P.S.
Driving on the left evolved because it leaves the right hand free to hold a whip, a can of beer, or to bravely gesticulate at other road users.
P.P.P.S.
If you think American English is bad, what about French English? Let's take a look at that next time kids