1) I would ask my 3x Great Grandfather, George Thomas Myatt, who exactly he was. I can find no trace of him at all before his wedding day.
2) I would ask my 3x Great Grandfather, Adam Grosert, what happened to him after he divorced his wife. He disappears after that date.
3) I would ask the son of the above, Thomas Grosert, what happened to his first wife, Christina Heggie. He took her and his son to America and by the time of the next US census he was living with someone else.
I'm sure i could think of a 101 more questions to ask, but those are the puzzles that frustrate me the most!