If your boss happens to share a name with a friend or co-worker, there's always a chance of accidentally selecting the wrong person with your email client's autofill feature. Macworld suggests assigning nicknames to those people who share names in your address book.
Macworld walks through the process of doing this with the Contacts application on OS X, but you can change the name of a contact in pretty much every email application (for Google, just head to the Contacts tab, click the name of the contact and edit it). For instance, if your employer's name is Adam, and one of your co-workers is also named Adam, change boss Adam to "Boss" to avoid confusion. This way, autofill won't select the wrong recipient. Head over to Macworld for the full guide.
Deal with email annoyances [Macworld]