Once upon a time, there lived a businessman. Before sleeping, he always used to take a glass of milk. As his business grew and he became richer, he thought that instead of daily preparing the glass of milk, he should better hire some servant for this job.
Soon, he published advertisement for the requirement of a servant and hired one servant. The servant initially served the milk properly to the businessman. After few days, the servant thought if he could just take out a quarter of the milk for himself and mix water in it, the master would never know. So, he took a quarter-glass milk out for himself and mixed water in it. The businessman started doubting that something is wrong with the glass of milk as it doesn't taste like it used to be before. After few more days, the doubt became stronger.