Speaking as someone who disappears waaay to frequently to have an excuse, I'm so sorry.

Work and school are usually contributing factors to sudden vanishing, and both at once is like taking a haymaker right to the role-playing face.

But that's only valid sometimes. More often than not, people just lose interest or grow impatient, especially when the beginning of a plot is conversation heavy. In one RP I was in, I kicked a guy out of a tree on the very first post. I like to believe that if the whole reason I lasted for the whole duration.