I remember S Voice on my Samsung Note. It was awful. When I got the S3 it was better but still not prime time. When I had the Note 2 it was actually useable. With the S4 it has been improved slightly again. So sending messages or updating Twitter is fairly simple. I have tried having some fun with S Voice.
I have tried asking S Voice if it’s ever used an iPhone and after a few attempts I got the response “No, I have standards.” I also tried asking it “Are you Siri?” and the reply was “I like to think I am.”
See if you can get your S4 to respond the same. Clearly somebody at Samsung had a sense of humour.