The first ones shown are quite neat and pleasant. The "accidental" ones pretty quickly gave me motion sickness as I scrolled through them. They also weren't nearly as interesting, though I couldn't look at them for very long.
Yeah, I'm not prone to motion sickness, but that wigglegram with the iPad gave it to me instantly.
The intentional ones tend to move along a horizontal plane, and in fairly uniform (or specifically-graded) steps.
The unintentional ones deviate on both bases, creating a more chaotic result.
("Creating chaos" being an interesting notion itself....)