Ah yeah, I remember the O'Brien storyline. She came back as a wild child after having lived in a wilderness-type of area. No memories of her parents, or even human language in general.
There can be bad consequences to time travel. That's why, in Back to the Future, Doc didn't want Marty meeting himself or Jennifer coming along. Personally, I'd love to see those consequences explored in a fic. What if future Lois, knowing Clark's secret, traveled to the past and met herself before she knew Clark's secret, and told herself? That could be interesting.
