In my opinion:
- Inbox is cluttered with emails caused by others using the “Reply to all” option.
- Incompatibility/lack of clarity between email subject and content.
- Big and Non-Uniform Signatures.
- Emails in other languages without English Translation.
- Email Firewalls Changing Subjects.
- Emails from iPhones which ruins the format of the complete email chain.
- Receiving useful and new information.
- Messages include audio/video attachments that assist in understanding the content.
- Messages include links to sites that broaden the knowledge base.
- Keeping Email Body Short and Precise.
- Good Formatting of Email Body with Clear Information/Action Items.
- Sending Meeting Requests instead of mentioning about Meetings in Email Body.