Pretty much anything relating to their character can provoke a reaction. I told Stitch I loved him and related to him because I am also cute and fluffy and I got a giant hug and kiss. I've had a conversation with Alice about if she still likes to play cards. I was in Garden Grill and Chip was near us, waiting for a waitress to finish dropping food off at a table before he went up to them and we told him he could sit with us, and maybe we could order a nice almond tart or something for him. He bounced a little and pulled out a chair, but then the waitress left the other table and he did the little "shucks" motion and hung his head. Tell Woody to reach for the sky and watch his reaction. Yes or no questions or statements for the furry characters work out pretty well, and most of them can mime answers better than you'd ever imagine.