Last week, I wrote about the joys or otherwise of being asked to critique someone else's work as a favour, and offered some suggestions as to how to survive the process with all your friendships intact.  This week, I want to share some of the pluses that linger after feeling flattered has worn off.
Editing or proofing someone else's work makes you more aware of how you write yourself and of any bad habits you might have drifted into.  It teaches you to take an objective look at what you do, as if you were a reader coming to the piece fresh with no prior knowledge of what it's about.  This distance soon highlights shaky structure or plotting, repetition or gaps where you assume readers have information you haven't given them.
If you still don't fancy picking over someone else's work, here are a few excuses you could try: 
* I was researching goatherding for my next novel and a goat ate your manuscript;
* My neuralgia's playing up and I wouldn't want to risk twitching and deleting everything;
* Your file crashed my computer and now all I get is the wheel of death.
No one will ever see through them–honest!