UML Diagrams- How large is too large?

I just printed what has to be the single largest sequence diagram I have ever had the distinct displeasure to read... it was 3 B size plotter pages. This begs two questions: 1) why would anyone make a method that large and 2) what use is a sequence diagram when it has to be hung on a wall and considered as if it were a great painting?

I am growing more convinced that a sense of elegance is the hallmark of a truly good programmer; much of the code displayed on this diagram is redundant and could easily be consolidated into a single method.