Right now, I'm reading Crazy Love, a great book by Francis Chan. I recently read a chapter in it on lukewarm Christians. Near the end of the chapter, Francis Chan shares a quote from John Piper's book, God Is the Gospel. This quote is really a question, and the question is meant to discern whether you really love God. Be warned, it's convicting.
"The critical question for our generation - and for every generation - is this: If you could have heaven, with no sickness, and with all the friends you ever had on earth, and all the food you ever liked, and all the leisure activities you ever enjoyed, and all the natural beauties you ever saw, and all the physical pleasures you ever tasted, and no human conflict or any natural disasters, could you be satisfied with heaven, if Christ was not there?"