I'd like to say plot, but I watch so many cartoons that have no plot at all... Let me put it this way: if a show has great characters but little to no plot, then those better be some DAMN interesting characters. But in order to give them any real development, it (usually) takes some kind of plot to go along with it. That could be something as simple as a love triangle.
On the other hand, a show can't rely on plot alone and be good; it needs a worthwhile recurring cast to intertwine with that plot and MAKE it good. Plus, let's be honest, people judge shows based on the faces in it. Never just the plot itself.
Think I'll go with characters, since a show can exist without a plot but not without those. This thread has me wondering if show producers work on story or individuals first... I'd like to think it's simultaneous, since that's the way I do it. It's probably more like, "Hmmm. I really like this OC I've made...what kind of world can I put him in for his existence to make sense?" Or something.
