God, do you really answer prayers?

Everyday millions of people take a portion of their time to speak to their God(s) however is it actually worthwhile? Or is it just the unheard pleas of humans trying to find answers for questions which are unreachable? We are going to consider a couple aspects of prayer. What does praying accomplish in reality? Which prayers are listened to? Action versus prayer. Self affirmation and placebo effect. Is there any scientific evidence for prayer?