I find the present time to be the most mysterious; anything could happen at any time, good or bad; people can come into your life, while other people leave it for good. You could start embarking on a new adventure right now; all it takes is one split second or minute where everything changes. I don't consider the future mysterious. It's just the day after today; for some, it may never get here. If there's going to be any mystery, it should be in the present time and not in time that has not yet arrived.
The past is history
The future is a mystery
But the present is a gift !
I like the unknown for mystery.
Put me down for 'future.'