I prefer for people to wait for me to finish. To move the sentence along, or try to guess what I am trying to say, it tells me they are growing impatient (which adds to my stress levels, which makes me stutter worse), and when they guess wrong, a lot of times I have to go back and say things again, which only makes things worse. To have a conversation with people who I know will wait for me to finish, and won't try to push the conversation along relaxes me, which over time makes me stutter easier.