Hmm, random traits...
I think I pick up on body language the most. Besides a couple facial expressions I might pick up, it's sitting styles that really stick with me. Like leaning forward and gripping the chair I think I got from Edward (cowboy bebop), and not actually sitting on but just crouching on a chair was from Night Crawler (I know, it's not an anime), and of course there's L and his sitting style, but it's not very comfortable, so that only happens in certain types of chairs.
Also eating habits. If I watch an anime that shows a lot of one type of food, that food must be mine within one week, or none shall live to see the light of day again.
Good thing I can cook.