For the fandom, finding out the fourth season will be the last.
Pepper's "I'm Sorry" song from Penny for Your Laughs. The whole song shows Pepper trying to cheer up Penny Ling only to fail miserably. She offers Penny a balloon, and it gets popped by a bird. She offers her an ice cream cone, it falls on her head. She tries to play catch with her with different balls, and each time Penny gets hit by the ball. Finally, Pepper gives Penny a flower, and when Penny sniffs it, a bee comes out of it and stings her on the nose. And to make this even more of a tearjerker, Penny cries at the end and her tears form a broken heart on the ground.
Vinnie going into a Heroic BSoD after being harshly rejected by the judges in "So You Skink You Can Dance."
Blythe's reaction when she temporarily loses her ability to understand animals in "What Did You Say?"
Zoe's reaction to Blythe altering the birthday dress that was made for her in "Terriers and Tiaras."
The season one finale in general. Blythe leaving to fashion camp for the summer. Think about that.....
In "Commercial Success" when Mrs Twombly, who was very excited to be in the commercial, was cut out entirely, Kathleen Barr does such an authentic cry, that you can't help but feel sorry for Mrs. Twombly.
Pepper in "Sweet Pepper", she spends most of the episode upset because she can't bring herself to talk to Captain Cuddles without punching him. She's so stressed about it that she actually snaps at Buttercream at one point.
In "Sunil's Sick Day" when Sunil and Vinnie imagine what life would be like without the other when they start to miss each other.
Russell on the verge of tears in The Hedgehog In The Plastic Bubble due to his quilling problem.
In "Stand Up Stinker" all Pepper wants is for humans to appreciate her jokes. Despite her wish coming true (her jokes appearing on a nightly talk show) she still will never get the credit.
Not so much Tear Jerker, but you do feel really bad for Penny in "Secret Cupet" when she gets more and more upset with Russell's flirting. She sounds like she's about to cry when she runs from him saying she needs a vacation.
In "Hamster Hoods" we see two stray kittens drinking dirty water in an ally. The two guest pet hamsters were able to cheer them up with toys but it's still really sad.
Jebbie's problem in "Tongue Tied" was pretty sad. Imagine, you're separated from your owner, lost in a giant city, knowing nobody, no-one there to help you, except one human. Except said human doesn't understand what you're trying to tell her, and you only have a few hours before you and your owner will be separated forever.
Penny Ling's dilemma in "What's So Scary About the Jungle? Everything!" She gets the chance to meet the host of her favorite show, only to discover that she's deathly afraid of her. Penny Ling becomes so depressed because of this, that she doesn't even laugh when Minka tickles her. Poor Penny.
In "Feud for Thought" when the Biskits separate. During lunch, you can see Whitney sitting alone at a table, looking positively heartbroken/devastated. Woobie indeed.
Kind of sad when you think about it with Dolores the Slow Loris. All she wants is to be taken seriously as a mature adult, but everyone keeps condescending her for things she can't help. (Being very cute with a high squeaky voice)]]
In "The Secret Recipe" when Blythe tries to tell Youngmee that her pet treats are terrible, and makes better treats (To switch them with) only for Youngmee to think she's trying to outdo/sabotage her. Ends up with Youngmee heartbroken on whether their friendship is falling apart, making Blythe cry too.
In "The Tortoise and the Heir", after Vinnie and Penny Ling interrupt Blythe's video blog, Vinnie overhears Blythe venting to Youngmee that she will never speak to them again. Not realizing she was only venting, Vinnie believes this and starts tearing up. Russell starts believing this too, when he tries to get Blythe's attention but she's too busy listening to music. The pets then imagine themselves in a Jetsons-style future taking place 150 years later where Blythe still doesn't talk to them.
In "Guilt Tripping", after Pepper accidentally broke Vinnie's lucky rock]], she tries to talk to a heartbroken Vinnie, tearfully talking to his broken rock. Pepper is shown crying while Vinnie emotionally derails, which really shows how awful she feels after the mistake she made, and that she is just as, if not even more, heartbroken than Vinnie. Turns into a Mood Whiplash however, when Vinnie reveals he has a bag full of lucky rocks.
The B-plot of "Two Peas in a Podcast" involves the pets thinking Penny Ling is moving away. (which she is, but just to a different room in the same apartment.)]] The pets do everything they can for her "last days" to make them as memorable as possible. Penny goes along with it, but she soon admits the truth near the end, and everyone cries, partly because of happiness and partly because of the raw onions Mrs. Twombly is cutting.
"On the Same Page". Hoooo boy, where do I start? While reading her mom's diary, Blythe reads that the ability to communicate with pets can suddenly disappear. Both Blythe and Youngmee are shocked by this, and throughout the episode, Blythe tries to use different ways she can talk to the pets, all of which failingmiserably. The B-plot is not much better. The male pets and the female pets argue about each other's "junk" and decide to separate, possibly forever. The icing on the cake is the song "To Tell You the Truth" which is told from all three perspectives.