She acts age inappropriate
Everything I see her in, she acts like a silly young girl. That juvenile squeal she alway uses is something a young girl might do but, she is too old to be acting like that. It is not cute. It is age inappropriate.
She is always playing a love struck little girl. I have never seen her play a mature woman. In contrast, Reese Witherspoon, who is approximately ten years younger, has played older, more mature women. For example, Four Christmases, a stupid movie, Witherspoon plays a single woman who is getting tired of being single. She comes across as much more mature, wise, introspective and serious than anything I have ever seen Parker ever play.