As long as I'm not getting any work done, I might as well make a list. If you can think of any others (and they must be attributed either to a philosopher or a philosophical school) put them in the comments and I'll add to the list.
1. Because there are an infinite number of halves between any two points, I was unable to traverse the distance from by bed to my desk. (Zeno)
2. I could be deceived about the existence of my paper. (Descartes)
3. Since there is no certain knowledge anyway, I figured, why bother? (Hume)
4. I was unable to ascertain the prompt nominally and hence dismissed it as an unworthy artifact of mere phenomenal experience. (Kant- submitted by Andrew)
5. What is an 'essay', anyway? Eh? Ah-ha! Too slow! Gotcha! (Socrates- submitted by Andrew)