You get to ask only 1 question to the you of the future.
What would you ask?
I have some pretty good ideas of the advice I would give younger me, so I think I would ask him, "What advice do you have for me". He's got a better idea than I do.
"What do you wish most I had done differently in this period of my life and why?"
I often imagine communicating with my future self, usually when I am frustrated or anxious, or disappointed about a relationship, as a way to gain perspective. I do this in both directions, thinking back to times in the past when I've imagined my future self and deciding what I would say now to me then.
With regard to disappointments, I often realize looking back that I'm glad I didn't get what I wished for.
To the 'me' of the future? Well, that's simple enough. "How does it feel being dead, dude?"
@silvereyes -- Well, in my case, I'd have to limit my trip into the future to something rather short term in order to avoid that scenario. Seems an awful waste of a time machine. Sort of like driving that new Ferrari to the end of the driveway and calling it quits.
Did you ever figure out where that other dollar went? Naw, just kidding. I figured that one out, long time ago.
I don't know. I'll have to think on it a while.