How old is your son?
I remember fondly of looking through Christmas Catalogs and watching commercials back between the ages of 5 - 8 and imagining what some of those toys would be like if I owned them. My imagination would run wild with unrealistic expectations (but seemed perfectly logical and realistic to my young brain). Toys could never live up to 80% of my expectations.
Part of this was just not enough information. The other part was trick marketing. Ever read the fine-print text on a commercial that disappears within .005 seconds? It's there specifically for kids like myself and to absolve themselves from false advertising... but what 7 year old reads that while engrossed in a commercial (if they can read and comprehend the disclaimer at all)?
Your son might have the same unrealistic expectations of this R2D2 robot, thinking that it is self-aware and can think and react in the same manner as the R2D2 in the movies. It's my understanding that while the toy can learn some cool stuff, it is more like a glorified furby or
robot dog.
Edit: I am remembering tons of stuff that I had unrealistic expectations over. Quite a few of them were products advertised in the back of "Boys Life" magazine. X-Ray Specs, "Learn to Throw your Voice," "Build your own Hovercraft," etc. What utter disappointments. Not only did they take weeks and weeks to arrive (an eternity to an 8 year old), but they definitely did NOT work like I expected them to.