Why Mormon Prophets?

I got to meet with a couple of very nice Mormon missionaries the other night and they kept bringing up how they have a living prophet today.

So I asked a very logical question: Has Gordon Hinckley given any prophecies that I need to hear about? (Hinckley is their current prophet – their prophets are voted in)

They responded "Oh, yes!" and gave me a pamphlet on how important marriage is written by Hinckley. That's not really a prophecy, that's just good common sense.

What else you got? "Well, Hinckley prophesied that the Nauvoo Temple would be rebuilt and it was!" Okay, but city planners make this sort of prophecy all the time – they've got the money, they've got the men, they've got the equipment, they've got plans and schedules, where's the prophecy in that?