It's quite irksome when shapes don't flow; not that everything should match up (because, let's face it, a shoe shaped like a dress would look incredibly awkward) but a harmonious flow from torso to legs to feet as translated through various textiles is always appreciated, never overlooked.
Mischa Barton's shapeless sparkle contraption is awkward enough (the girl DOES tend to wear sacks) without the bulky shoe-box looking footgear she's got on, but if she had worn something daintier -- perhaps something in the way of a peep-toe pump in the same color or even a standard pointy stiletto -- she might have knocked out that bulky-twiggy-bulky theme and actually had length and grace.
And Lily Allen, she who most likely couldn't give a shit about the dubious harmony of her outfit nor what I think about it, is actually wearing one of the most flattering dresses I've ever seen gracing her body -- and I'm positive that it's not because her waist looks so tiny in juxtaposition with her alarmingly large feet. From mid-tibia up, Lily looks... amazing. Look at that hair! The attitude of her whole face with the sexy aviators, red lipstick, and girlish star earrings! Now look at her giant boots, which you know she totally could have rocked with a cute mini or encasing ripped jeans.
I know, disappointing.