Sender's Remorse
The emotion experienced when one immediatley regrets sending an Instant Message (IM) Usually in reference to ex-girlfriend/boyfriend or annoying friend. Usually happens when the sender is short on sleep or has succumbed to their emotional instability.
I just sent an Instant Message to an ex-girlfriend in hopes of repairing a friendship, but now I realize that having done so will probably make the situation worse and
Sender's Remorse
The feeling you get almost immediately after you have responded to an email or text, that caused you to become irate.
I replied to my manager telling her she's being insubordinate. Damn, I think I'm having sender's remorse, hope I don't get fired...