In undergrad, a friend of mine always said this whenever I started with a "But..." or "What had happened was..."
Excuses are tools of incompetence, used to build monuments of nothingness.
There is no place for excuses in your portfolio or at work. So what if you didn't have a writer? Or if you're art director was lazy? Or if the assignment changed at 2am? Or if you didn't hear the instructions correctly? Or if it's a holiday?
There is work to be done. Do your best and keep on trucking.