Happiness associated with the 'feeling of completion'

Completion of tasks or work always leads to complacency. Completion of school, completion of college, completion of degree each tend to add brick by brick to build a human being. These completions are essential for an individual to achieve great happiness. Completion of an exam, used to provide a lot of relief and happiness during good old school days.
The new item added to this cart is - completion of a day, then a week, furthermore a month in office. There is a specialty associated with completion of a month in workplace as you get money and debit card into your hands.
Software engineers are known for their frequent job switches' hence their stay in a company, even for a month is valued. Although completion is good in a sense, it also reminds of more responsibilities.
Happiness at various culminations is not the same. The purity of happiness from childhood to present situation is drastically reduced. Change has influenced happiness too. . .