Being blunt doesn't always pay off!

Some may wonder, does it ever?
So my boss emailed me a resume the other day and asked me what I thought of it. Me being me, completely honest and straight to the point told him exactly what I thought. I believe the last line I wrote was 'If you want to know what I really think", just a tad sarcastic.
When I replied to what I though was him, I replied to the attachment and it went directly to the recipient of the resume.
Oops! Luckily I have a pretty easy going boss so he wasn't too upset.
I didn't even realize I had done this until I received a reply from this guy. At which point I turned purple and about 5 degrees hotter.
His reply was quite tasteful, which was a little bit of a relief.
AWKWARD.