A piece of black tarmac walks menacingly into a pub and demands
"Give me a pint of beer !!! I'm hard !!"

The barman, feeling suitably threatened, gives him his drink.

Moments later a piece of red tarmac walks into the pub, storms up
to the barman and growls "Give me two pints of beer - NOW!!!  I'm the
hardest piece of tarmac in the World!!!!"  The barman is terrified
and quickly hands over the beer.

When the piece of black tarmac has finished his pint he returns to
the bar and demands another.  The barman, no longer so scared of the
black tarmac, points out that a piece of red tarmac is in the pub and the
piece of black tarmac looks worried and starts to back off.

"What's the problem?" asks the barman, "Why are you so freaked out by the
other guy?"  The piece of black tarmac looks nervously around and replies
"Don't you know, that red piece of tarmac, he's a cycle path!!"