Let's start with a statement of courage; Even if there is absolutely NOTHING to live for; a FRAUD is STILL a FRAUD! We cannot hide behind a fraud, hoax or spiritual conman because we're afraid of the flesh and blood REAL world! By asking this, a Christian reveals his own insecurity. If Jehovah is just some ancient, mythological, tribal god... THEN WHAT?
What is there to live for?
In short, it's better than the alternative! Biologically, we live to pass on genetics to the next generation which should be better adapted to the environment than we are. Emotionally we live to experience joy, happiness, exhuberence, love. We live for all those exciting and wonderful things that happen in the short span that we're alive. Wouldn't it be awful if we were just the puppets of an uncaring and vicious deity that would sentence us to eternal damnation because we happened to be born in Malaysia and never gave Christianity a second thought? My joy, my happiness, my whole quality of life increased dramatically once all the chains and responsibilities of this mythology fell off of me. Isn't living for yourself and your family so much more fulfilling than living for the approval of some 7,000 year old tribal deity or a 1st century cult leader?