What looks iconically CG tends to be lighting looking a bit off. Like, say, plastic. Because to maximize parallelism the Depth Buffering Algorithm used very approximate formulas, though we've now overcome this with Recursive Raytracing!
Also if you don't put enough human or computer effort in, animations can look a bit stiff especially especially in the early days. But it will always look smooth thanks to interpolation!
2/2 Fin! Tomorrow: vector graphics.