Jimmy Neutron always uses the same 6 or so (adult) background characters, so it doesn't take long for anyone to recognize them. I'm not sure if any of them have names, however (I believe one of them is Cindy's dad, but I'm not positive, and he still doesn't have a name as far as I know). They don't particulary scream "lovable" to me, though, and it's actually kind of boring to see them so many times. It's like, how about some variety?
I do love the background characters on Pucca, though, and usually remember them. The girl with the accent and tendency to freak out, have her hair turn wild, and start singing is my favorite, though.