30 vs 60 fps - can you really see the difference?

[IIIIITHE1IIIII]

hershel_layton said:
When I play mariokart, I can easily tell the difference from when I'm playing alone to when my sister joins me.

30 FPS looks more choppy compared to 60 FPS

 

That's funny because the game still runs at 60 fps during 2-player splitscreen.