It's ALWAYS important to pay attention to what you're doing, even in the realm of writing. When you're driving, distractions can kill (DON'T TEXT!). When you're working a crane at a construction site, distractions can kill. When you're baking a cake, distractions can kill... your cake. And the same is true with manuscripts.
I say this because I recently received a rejection from someone whose query guidelines ask for 50 pages of the book. That's basically a cold-query with built-in partial. Now there are many reasons why I could've received a rejection, but if forced to guess, I would have to say that I missed some GLARING continuity errors!
How could this happen? I wasn't paying attention. I found these errors just this week while going through and making changes based on feedback I received at the conference. Sure, they only commented on the first ten pages, but other people want to see more of my work. I figured it wouldn't hurt to go through and make sure it's as clean as it possibly can be. And I found some issues.
Missing words or misplaced commas (if they're few and far-between) may not do a lot of harm in the long run, but I felt like a complete newbie when I found sentences that pointed back to conversations I wrote out of my book. Honestly, if I was an agent considering that work, I would've rejected it, no matter how solid the rest of the writing was.
Again, I only got a "Dear Author" response, so there could be many reasons why I didn't get a full request. But poor writing is always a good indicator.
Now lest you think that I'm here to complain, I'm not. I'm excited because people DO want to read my book! And I'm laughing about the mistake I made because it was an easy fix, and I can only blame myself. Beating myself up would be a waste of time. I learned my lesson, and I hope to pass on a grain of wisdom to all of you.
Now I'm off to work. I'll pay attention today because I'm probably going to be driving a truck. Or operating a forklift. The only deaths I plan to cause will be fictitious characters in novels that I write.