Genealogy....

For a few years I have been working on my families genealogy.  At first I started on my dad's side, only to go back as afar as my grandparents, I have a name of a great grandpa but that's all I have.  So frustrated I started on my mom's side, I got as far back to my great-great grandparents. But then I hit a snag, someone popped up on a census but ten years later they were no longer on the census with the rest of the family.  I have searched online for birth records, death record, nothing has seemed to pop up.  I even asked my uncles if they knew anything about this misterious family member and nope they didn't know, they thought grandma (their mom) was an only child. 
This is why I want to make these family trees, My family has kept their past quiet and so us future generation doesn't know anything about the past.  It's a shame that we don't know much.  Maybe since I have questions, wonder who people were maybe someone else in my family have the same questions.  Who was our ancesters?