I don't like designing under a time constraint because I have to skip a lot of planning steps. However, I know that sometimes I will have to do things this way, so I'm going to try to streamline my workflow as much as possible.
I actually kind of liked that someone else had started the project already when I began working on it. Having a partially laid-out comp gave me a direction to go in. There wasn't much done but it was enough underlying structure for me to build on.
If I ever work for an agency, there may be times when I am working with a team and we are all contributing to parts of the design, or I may have to finish a design for someone else because they got sick or something. If I continue to work freelance, there may be cases where the client tried to start the design but didn't know what they were doing. Or the client may have already had a designer but they quit and disappeared in the middle of the project, leaving a half-finished design that I will need to complete.