To the non believers: if you saw first hand with your own eyes someone perform a feat of extreme accomplishment (parting a sea etc) or witnessed a personal miracle would you then open your mind?
Exactly. You cannot conclusively prove God (or some higher power be that God, Buddha, Allah, Krishna, whatever) does or does not exist. However people form their own opinions based on their own life experiences (or lack thereof).
Everybody loses motivation at some point (including myself). I usually refocus by just doing whatever it is that is distracting me instead. Then when I get bored to that I can get back to work.