Being Dumb

My owners say I am dumb and look dumb. It isn't my fault that I am. maybe it is because I hit my head one to many times. I don't feel it, I just get up and walk it off.
My big sister(two-legged) likes to knock me on the floor and plays with me, she slids me across the floor on my side and I get up and go back to her, so she can do it over. My owner (her sister) says she's mean. How do I convince her I like it? So maybe I am dumb