People who hate children?
Fun fact: When I re-watched parts of the series recently. I actually had a much better opinion of Renton and the kids. Used to be one of those guys who found both of them annoying to the core, but I was a teen back then, and I'm now a adult, so maybe it's part of my maturation process? plus not to mention I work in child care now and am studying towards becoming a school teacher, so maybe my tolerance levels for children has increased as a result of that? .
Really, the only character that outright annoys me in Eureka Seven is Holland. (whom I thought was a bad-ass when I first watched it heh).