I had always wondering that, but during my reading of The Purpose Driven Life, By Rick Warren... if people aren't famarliar with that its a book that has a reading for you each day, an through out it, it helps you realize "what on earth are you here for " and to help with your walk with God...... in one of the daily readings it was talking about the difference of that.. i can't find it right now... what it says exactly.....(sorry)
Good book though, answers alot of questions... Easy read, enjoyable for people that really don't like to read also!