Life has no meaning. Society comes up with all the BS so that we are busy living “lives”. The truth is we are all going to die someday. Nothing is forever. We have chemicals in our brains keeping us busy with the “feelings” and “emotions” Deep down we know that nothing is really matter. Since we are already here, it’s best to do things that make us “happy” and do no harm to others. Be kind, be humble, be happy.

whats important in life? Being happy or at least content with yourself
why do we live and what for ? There's no reason for it, life just is an accident of birth
what is reason ? Accepting and attempting to understand reality without resorting to fantasy
what is common sense ? A myth more often than not
why do we keep on going , i mean mankind ? We don't really have a choice, survival is hard wired in to our biology *

what is important in life is up to whoever's life it is. what is important to me might not be important to you. this is not something that can be decided for you by strangers on a website, or even by people you know. you decide.

likewise why we live and for what. why, of course, is because our species procreates. for what is up to you.

reason is the ability to look at evidence and figure out what it means.

common sense is uncommon. a dictionary will help you define it but not to have it.

why mankind keeps on going is because that's how we're wired.

g

Let's see...
Health and social contact.
Because our mothers offered their bodies for about 9 months and for no special reason.
Reason is the ability to recognize structures and to draw valid conclusions from them.
Common sense is a set of rules that you learned as a child that you believe without questioning even though sometimes those rules are not common or even true.
We keep going because it is an evolved drive we have. If mankind didn't have this drive we wouldn't have made it that far. So only species with it can even ask this question.
You're welcome.