Demanding God for Stuff

It's the biggest rage again, it seems. Or maybe not. But lately I've been running across the same teaching I was exposed to when I began my relationship with Jesus. I loved it, of course. Who wouldn't. I was taught essentially to demand God for stuff. I should just wave my magic wand, and boom. God would answer. If He didn't, I didn't have enough faith. After all, God put me on earth so He would be at my beck and call, right? Wasn't He here to serve me instead of me here to serve Him? Not. No...