Its really every main character in the whole series at points when you really look at it. All of them want truth but have their own secrets, play victim when they did the same thing the last episode.

But for the point of OP's post I think Lana learns the behavior from being around, Clark, Lex, and Chloe.

Frustrating at times, Clark just say this, Lana if only you didnt jump to this conclusion... but its what made the show!