I saw the first anime series before I read the manga, and Lust is still one of my favorite characters. I know this probably wasn't intentional, but I see her as a metaphor for villainized female sexuality. For starters, she's associated with Lust, one of the Seven Deadly Sins. While 'lust' is a verb, she is the embodiment of the object of lust instead (unlike the other Hommunculi, which embody the action). It makes for a really fascinating dynamic. Often, women are blamed for being objects of attraction, something they have very little control over. After all, it's the choice of the person observing us to objectify us. And while the Hommunculi are obviously not on the side of 'good' in this series, they're not the archetypes they first appear to be. Lust has memories she can't quite put together. She was created out of love but then scorned. And someone cruel was the first person to be kind to her.
Plus... this scene. It's so good.
She's cruel. She's conflicted. She's determined.
I love how complex she is. Watching her through the series was amazing.