Sharing Information

How do you share information with someone via email, and not make them think you're nutty? I've had this as an issue with a cousin I found last year. I had already managed to track down a lot of information on the family through the computer but I knew that there was a lot more that I was missing, especially the personal side of the family. I think he thought I already knew everything, though, and there wasn't anything he could contribute. How do you deal with that in talking to people? Worry about how they'll take me kind of holds me back a bit, and I don't want that, not when I ought to be having fun and making the family tree sprout more branches to terrify the cat.