For me, I stutter WAAAAY more when I've prepared because I know what I have to say next...if you know what I mean? And when I think about what I have to say like that im always thinking "that's a hard sound, you'll stutter on that" or something, then I do. But when I'm just chatting with a friend its much better. Its like if I think about stuttering, it makes me stutter, but I can't just stop thinking about it! Because I'll be like "don't think about stuttering...don't think about stuttering..." but by thinking that, I am thinking about stuttering! A good example is yesterday, I had a Covid test in school, and I knew I would have to say my name, and I can't say my surname. Its one of those where I just block and no matter what I do, it ain't coming out! So I was worrying about it all day, and when I tried to say it I blocked (luckily the lady was nice so I told her my first name and she found me). But when I was walking home me and my friends were talking about our full names, and I just said my surname out loud no problem! Because I wasn't thinking "I'm going to say that next, and I can't" I just said it, so my brain almost didn't have time to remember that I was supposed to block when I say that!