When sending emails, the use of the subject line is extremely important.
First, the subject tells the recipient what the email is about. It should inform them whether it’s a pressing matter based on the topic (and putting the word “urgent” when it’s not urgent defeats the purpose).
Second, many email programs group messages based on the subject (with the assumption that emails with the same subject are related). They will group all emails with no subject together as if they are related. They will also group all subjects with the word “hi” as the same even if they are from different people.
For this reason, proper use of the subject line is vital for efficient email usage
Have a great day!