i just got one question

No, don't agree with you- she's a terrific young actress! But an actor can only do so much with the material presented to them. I'm sure she was only doing what the director wanted her to do. Material and direction, could explain why no one is absolutely amazing in this film. Daveigh's character has a "flat affect" throughout the entire film, and it's very obvious and continues from beginning to end. Of course during dailies etc the director/production team would have noticed this and immediately told her to come more alive etc if that's what they wanted. So it seems fairly obvious, this is how they wanted her to portray Samantha. This is an attitude/look that Daveigh can do well with her features. And I don't think it makes her a bad actress. She has always been amazing in Big Love. She was terrific in Without A Trace. Possibly you are getting her confused with countless other young "disney/nick" type "bounce off the walls full of spastic energy smiles giggles" actors? Daveigh has never been that type. Thank Goodness!