How software requirements sound in reality :-
customer :- can you build a ship from banana leaves that can travel faster than light and is pink in color ?
we will give you green paint , 10 workers and state-of-the-art nail-cutter !!
software engineer : no , that is not possible
manager : what if we add 2 more workers , some blue paint and a bottle-opener ?
software engineer : so how many ships do you want ?