BlunderDelay

BlunderDelay is a Thunderbird extension that gives you a little extra time to think about what you've written. BlunderDelay spares you waiting on the send progress dialog. BlunderDelay makes the Send Later command more useful by automatically executing the Send Unsent Messages command at regular intervals. If, in the minutes before BlunderDelay executes, you regain some sanity and realize you shouldn't have said something, you will still be able to edit or delete the message from your Unsent Messages folder before it gets you fired or divorced.