What is the purpose of life?

To be as nice as you can be under any given circumstance.
"One can go through life being oh so smart or oh so pleasant! Having tried them both, I recommend being oh so pleasant!"
Some people think life is measured in conquests, for all too many those conquests are sexual encounters (sperm and condoms are important to such people). Sexual reproduction is not a mandatory event for any living creature. While mandatory for a species survival for the individual it assumes the priority one places on it.
Just because your mind is not centered on your crotch is no reason to belittle yourself. Most intellectuals do not focus on reproduction or the pleasures it affords.
As one person said-
"Our purpose in life is to make our corner of the world a little brighter and cleaner then when we found it!"

To fulfill the purpose of life, you have to work at every angle you can at your daily task.
One must know the schematic or mind map to understand life.
But most importantly, you have to give out your love in your work.
(For example, Disney is work of love) Our purpose is defined by our actions, (e.g. act out of love can be a positive thing). When you give out to the best of your ability, your purpose is fulfilled.
The purpose of life is happiness, and there is work to be done in order to achieve greatness(happiness).

I believe the purpose of life is to experience it. Through this experiences, we may grow, learn, heal and have a better understanding of love. We are spiritual beings that want to experience the physical in order to grow. Here are some tips to help with that process: Do the best you can in each moment and then let go, knowing you could not have done anything any better. Learn to forgive yourself and others for mistakes as this is just the method of how we learn. Help others in some way, by doing this we help our self as well. Be thankful for everything you do have, having a grateful heart makes life a little easier. Pick a direction that you wish to go in and make choices that move you toward that direction. Take time to frolic, play and have some fun. Have a wonderful life. Take Care.

Personally, I believe there is no goal, no fate and therefore also no wrong or right.
Make your own goal, you are your own god.
I find this thought very liberating.
And I bet a thousand bucks that I could make your schoolmates feel stupid about the same subject.
The fact that you doubt a lot is a sign of intelligence ;)

It used to be to seek and get us much pleasure for myself in life as possible...but that never made me happy.

After I gave my life to Jesus Christ I was hit with so much love and joy that I can sincerely say that as a result of all that my purpose in life is this:

Seek God's presence through Christ and soak in as much of his love and peace as possible, while listening to the guidance of the Holy Spirit as I walk my daily life. The joy is indescribable.