Yeah, it happens to me all the time. There are words I have trouble getting out at work, but when I get home I can easily say them. Fast, slow, different rhythms. It's like I don't have a stutter at all. I don't know why I would feel nervous at work or with friends though when I need to be. Even more ironic is I am very good at public speaking. I can get in front of a room full of people I have never met before and easily talk. The most stuttering I might do is just getting that first word out. Yet with friends I have known for years every other sentence can be difficult sometimes. It can be quite annoying, especially when you are trying to get a word out and the other person thinks you are ignoring them or don't care to say anything.