Perhaps at one point or another we've all made the mistake of inadvertently sending an e-mail that either was not completed or contained content you decided to discard. One scenario is you open Mail and start composing your e-mail, and then when clicking the window buttons to close or minimize the message window you inadvertently click the "Send" button that's right below the window buttons. Additionally you might decide when composing an e-mail that you want to use a hot key to access some feature in Mail such as the color palette with Shift-Command-C, but may inadvertently hit the "D" key instead which will send the message.
These scenarios likely do not happen frequently, but if and when they do they surely can result in anything from mild embarrassment and apologies, to someone needing to do a decent amount of explaining. There are a couple of things you can do to help avoid these problems:
Reorganize Mail toolbar
By default Apple puts the "Send" button right next to the window management buttons (close, minimize, and zoom). Therefore, edit the toolbar and move the Send button to a different location. You can put a blank space to the left of the Send button to push it away from the window buttons, or you can move it wherever you'd like on the toolbar such as to the far right or in the center. Doing this will make it far less likely to inadvertently click the Send button.
Address or title only when ready to send
Even with the Send button out of the way, you may still inadvertently send your message off, but this can only be done if your message is addressed. Unfortunately many times we get into the habit of composing a new message and specifying who we're sending it to right away, before we write the message itself. Therefore while the message is still in draft form (or even containing thoughts we might not want to send), the message is fully addressed and ready to go.
If you would prefer to address the message before composing it, then a second option is to forgo titling it until you are ready to send. While a message without a subject can still be sent, if you do so then Mail will first show a warning about the message not having a subject, which may be enough to notify you that you inadvertently told Mail to send the message.
Do you have any tips for how to help avoid inadvertently sending Mail messages? If so then post them in the comments below.