Depends. If I have a character driving the keyboard, it's sometimes a better idea than what I plotted, so I just let the story be steered. I can't tell you how many time Sheppard/Lorne tried to divert East/West, and I had to keep slapping them down. Usually, if I really have to stick with plot, I will not write any reaction or 'emotional content', but get the plot down, and then go back and figure out what the reactions are to the existing story line.