I can only speak from personal experience. I have been a stutter all my life and I frankly stopped caring after I turned 15 or so. So my point is what I’m about to say comes from the experience and perspective of someone that is self confident, someone that actually married the hottest chick of his class and whom all of his friends wanted to date. I don’t like it when someone finishes my sentences. I also don’t like it when they look away. My wife never does that and she talks to me like I’m “normal” and I can actually speak to her freely without a care in the world. That being said sometimes the both of us laugh at my blocks. Just today I dragged a single vowel for three seconds and she ended up laughing her eyes out and so did I. I couldn’t care less. She looks cute laughing and I know she doesn’t care that I stutter. So, to summarize. I think most of us want to have a normal conversation and part of a normal conversation is people not looking to the ceiling when we hit a speed block or finishing our sentences. Actually my mom does that and it irritates me and my wife actually noticed and tells her, but that’s for another day.