Parts of the plot were reused from "The Mail Animal". Both episodes have a new mailman (Mr. Letterman and Stu respectively) who replace Herman to deliver the mail. They initially do not believe that Garfield is a threat until Garfield gives them a barrage of traps, leading Herman to reclaim his job.
Garfield's 7 Steps to Harassing a Mailman Successfully
Establish a climate of confidence. Let him believe he's safe at first, even if you have to demean yourself a bit.
Showtime
Make life interesting
Think big
Think bigger
All-out war
Give yourself a pat of the back for a job well done! And celebrate in style!
Goofs
When Stu approaches the mail slot in a fake bush, Garfield's eyes are visible in his bush.
When Stu skips out the post office, he is not wearing a mailbag. The mailbag reappears when he is laughing.