This question already has an answer here:
I often experience people who when they get to the end of what they were saying, they finish their sentence with the word "so" as if they are going to say something else, but they don't.
Example: "I asked him if he would fix my computer, but he said he didn't have time, so..."
I ran an "experiment" on a friend who does this all the time, and after he finished his sentence with "so," I didn't say anything. He acted as if he was done speaking, even though I waited for him to continue. I finally said, "So...what?" He said he had nothing else to say.
I thought to post this question here when I noticed the man in this video also finish his sentence with "so" but not have anything else to say:
https://www.facebook.com/video.php?v=845994225437919 (start at 1:10)
Why do people finish speaking by saying "so" when they have nothing else to say?