You can opt staff out of specific email templates by customizing the "Email Templates to Exclude" setting on the "Email Settings" section of their staff profile.
if you go to a staff member's profile, under the "Overview" section, at the bottom you'll see their email settings:
If you edit the Email Settings section, you can turn off templates for just this staff. So say this staff did not want to receive reminders for their appointments anymore. I could select "Appointment Reminder" in the "Email Templates to "Exclude" check list and then this staff would not receive the appointment reminder email anymore but all other staff still would: