I have had so many Christians or religious people ask this question after learning either that I'm not religious, or that I'm an atheist.

My response is (and has always been) - I believe in myself.

This is most often met with a look of disbelief and a comment or two about how self centered of a view that is.

Really? Is it really so conceited to have faith that I can overcome the obstacles in my life by working hard, making changes to my mindset and/or educating myself?

I certainly know that when it really comes down to it, I am the one and only person I can count on to have faith in me no matter what I'm facing - and that faith will never falter. Others will always have limits on how much faith they'll have in you, conditions that you must meet.