I had a very abrupt email

sent to me yesterday, abrupt to the point of being rude. I had, somewhat reluctantly, offered to do something. The offer was made in the belief that I was expected to make it. As it has been turned down it will mean less work for me but it does mean that a group of people will miss out on potentially valuable information. That can't be helped.
The person who sent it is usually very polite though and I can't help wondering what would happen if she went back and read her email again. Would she phrase it differently? Perhaps she was simply in a hurry and is unaware of how it would sound to the recipient.
It made me aware yet again of the dangers of email and social media. Blogs may not be quite as much of a worry. You can go back to a blog and made alterations. I removed something once because, although there was nothing offensive about it - indeed the opposite, someone told me she had decided she would rather it was not there. It didn't take much effort and I was willing to do it if it had  made her feel uncomfortable at it being there.
But emails are different, once sent they are sent. They are easy to dash off without too much thought...and they can just as easily be misunderstood. You don't get all the clues you get when you are communicating face to face or even just hearing someone on the phone. 
Some people will also endeavour to keep their emails short too. If the Senior Cat wrote emails (he doesn't)) then they would be very short. He is a "Columbus-method" typist - i.e. "discover and land". On the other hand I do so much keyboard work that I am a lot faster than he is and tend to write more. I am, I hope, less likely to sound abrupt.
But the email of yesterday came from someone who is definitely not a Columbus-method typist. I can only assume it was sent in haste and without thought as to how it might sound - or what the consequences might be.
Emails are not like letters. Once you hit "send" that is it. There is no chance of reconsidering your words as you prowl off to the letterbox.