The "whys, whats and hows?" of life

Each day is passing on like a jiffy. Everday i wish to list out what i "unlearnt" and what i "learnt" that day but not a day have i been able to jolt them down. but, recently, i have taken part in quite a few discussions with some of my friends on the intriguing questions in life like "Where is God?, What after death?, Why should men or How should men live?" etc. The whole purpose of discussions boiled down to a simple point - "The purpose of our life." Today morning, i had a discussion with one of my colleagues, Gopal, a very learned person who is a member of the ISKCON group. They (the ISKCONers) have crystal clear replies to many of common men's questions. Though many are axioms (which don't have a proof but are taken for granted), they furnish lucid explanations and examples which convince a common man. Why do these questions come for us during the post teen youth period? and has it got anything to do with Quarter Life Crisis?