When you go to your office, you know your agenda. When you go on a holiday, you are aware whether you will swim or surf or ride a horse or gamble.
If you didn't know the purpose, you could hardly do anything in the office [except for routine] or on a holiday.
Similarly, your real purpose of life, i.e. your advent upon this Earth, if unknown to you, then you can do nothing for the fulfillment thereof.
If you don't do anything for the fulfillment of the purpose for which you are here, upon this Earth, then there can be no pleasure [happiness] in life.
To know more about purpose of life and what is happiness Click here
http://www.energyhealing.in/purpose-of-life/