Here's a question worth sitting with, letting it goad you a little bit.
If there was one thing you could do in the world to make a difference, what would it be?
I ask that because (a) you probably know the answer and (b) God is probably calling you to do it, whether or not you've actually engaged in that activity yet or not.
What's holding you back? Money? Time? Frustration? A relationship? Opportunity? Good old-fashioned fear?
We not only have the opportunity to step out and experience God in this, we also have the obligation to do so. Without turning up the guiltometer to 11, please remember that we (yes, we, as Christians) will stand to give an account to Christ one day and be rewarded based on our obedience to Him (2 Corinthians 5.10). Our works really do matter.
So what are you waiting on?