Affectedly and self-servingly earnest
Make good or smarmy decisions that will affect the outcome of certain situations.
He's smarmy, he's immature and he's just plain mean.
The worst examples bring to mind images of a smarmy lady's man in a bad suit working his "magic" at the bar.
You can choose to be nice or smarmy (sarcastic).
No one can really say why someone like Brody Jenner who, although a little smarmy with the ladies, seems like a pretty okay guy, would ever be friends with a guy like Spencer.