I got a stacked (?) bob in the back this past month, and even though I make my hair curly, I'm sure it does that, too. I'm fairly sure, though, that no one is looking at my flip, but starin' at my hips or how else I'm stacked in the back.
[Yes, that is how I justify not spending an extra 15 minutes on my hair to get it looking right in the back. L-A-Z-Y.]