There are two kinds of convictions... those which man believes steer him or her towards the life they want, and those which incline man towards the heart of God. They are, of course, the same thing, as God made man despite not having any need for man, therefore man's deepest desire is known and satisfied only by God. So the difference is a matter of knowledge (or ignorance) of this fact.
True convictions, then, bears the divine mark of God's heart, and we know this because there is nothing like it that man has ever or would ever conceive. It is also, unabashedly, the meaning of life. Suspend your disbelief, because what you are reading is true...
The meaning (or purpose) of life is this: relationship. More importantly, relationship with God, followed by relationship with fellow man.
There are two prevailing natures in the universe, three if you count sitting on the fence between the two, and they are all classifiable within this scope of the meaning of life. That which unites in relationship and that which separates. You can call them good and evil but for our [human] intensive purposes it doesn't matter. And if you're sitting on the fence between the two, know this: collecting knowledge to make a decision is a futile effort, because it will never be about what you know, but who you know.
Do you know God? God wants you to know Him. Do you want to know what God is like? Meet Jesus. Jesus is God as a human, and allows us to see what God is like within the human paradigm. Jesus allowed Himself to be murdered so that "whomever" (meaning "any individual", i.e. you) can move from the side of the fence that is severed, separated relationship to the side that is united relationship with the God that made you and can give you the life that will truly satisfy you.
The deepest, soul-felt desires are only answered by relationship with God, and this relationship is only available from God reaching down to us through His life as Jesus Christ, not through our human convictions of trying to reach up to God (religion or going-nowhere morality). This is called the Good News because it means humanity has a way to have the life we deeply desire which is not founded on our fallible nature. It is based on the love of God and His design, the "meaning of life", which is you having a relationship with Him... this is done through belief in Jesus Christ, the mediator between God and humanity (being fully both of those things) so that God proves both perfectly fair and also perfectly loving.
Because Jesus Christ rose from the dead and is presently alive in this moment, those who entrust their souls to Him gain living hope that fears not even death, unlike hope anything on this earth which is fallible. Belief in the one and only living God is the way may not necessarily give you a state of being which our mere human minds believe to be the best (fame, wealth, power, etc) but will lead to a state of being which satisfies eternally the desires which these fallible things will only temporarily satisfy. You will live a life inconceivably satisfied compared to these fallible desires, and once you taste it you will gladly lose more of the temporary for the eternal fulfillment.
So to answer the question, every conceivable human conviction falls short of the purpose we intend them for because life is not about us.