Kaeloo gets a letter from someone claiming to be a fan of the show. The letter says that Kaeloo is boring and that the other characters are much more entertaining to watch.
"Let's Play Catch the Mailman" contains the following tropes:
- Bill... Bill... Junk... Bill...: A variant. Stumpy receives a huge stack of mail, and everything he picks up is either a bill or an advertisement until he reaches the end of the stack and finds an actual letter.
- Boring Insult: Kaeloo is on the receiving end of this in a letter from someone claiming to be one of the viewers. It turns out that the letter was written by Mr. Cat.
- Break the Haughty: Kaeloo receives a letter in the mail, and just before she opens it, Stumpy asks what it is. Kaeloo says that it's probably a letter from an admirer or fan of the show, and explains to Stumpy in a condescending tone of voice that the reason she gets one and he doesn't is that she's the main character of the show and the show is named after her. She then proceeds to open the letter, and it turns out to be a hate letter criticizing her for being "boring". And to rub salt in the wound, the letter also says that Stumpy (and everyone else) is better than her.
- Didn't Think This Through: After Mr. Cat succeeds in getting Kaeloo to get angry at him and therefore break her promise to stay calm forever, he realizes that her getting angry means that he is in for a No-Holds-Barred Beatdown.
- Foreshadowing: Kaeloo gets a letter in the mail from someone claiming to be a fan of the show, and the letter is quite insulting. It is addressed "Dear frog" instead of "Dear Kaeloo", foreshadowing the fact that the letter was written by Mr. Cat, who often refers to Kaeloo as "frog" or "froggy".
- Fourth-Wall Mail Slot: In-universe, in the episode "Let's Play Catch the Mailman", Kaeloo gets a letter from a fan of the show criticizing her for being annoying and boringnote . It ends up being subverted as the letter turns out to have been written by Mr. Cat.
- Inspirational Insult: Kaeloo receives a letter in the mail from someone claiming to be a fan of the show, who says that Stumpy, Quack Quack and especially Mr. Cat are the best characters on the show and that she is annoying, boring, serious and easily offended. Kaeloo decides to become easygoing and cool.
- Lotus Position: Kaeloo meditates in this position to keep herself from getting angry about the letter.
- Something Only They Would Say: Kaeloo figures out that Mr. Cat wrote the letter after hearing him describe her with the same adjectives that the letter used to deride her.
- Wham Line: "I'm telling you, Kaeloo! Loosen up... unless you want to stay serious, monotonous, and annoying?
