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Tear Jerker: Recess
Principal Prickly's speech in The Movie which manages to convince TJ not to give up saving summer vacation, while revealing the fact that Prickly himself was once a care free kid just like TJ.
Prickly: "I'll let you in on a little secret, Detweiller. Every adult you've ever known was a kid at sometime in his life. You think we don't remember summer vacation? Riding our bikes down the creek. Catching polliwogs in a jar. Camping out under the stars. Well you're wrong! Sometimes I sit there in my office, looking out at you kids in the playground and I think, "They don't know how good they got it. In a few years, they'll be grownups like me and all those good times will be memories for them, too". So go ahead. Put a whoopie-cushion in my chair. Put fake vomit on my carpet. Make fun of my "big, saggy butt". But don't ever say I don't care about summer vacation, 'cause those memories are the last part of childhood I got left."
Not to mention TJ's and Prickley's conversation at the end of the movie, with the villains quest foiled, Prickley having reconnected to his own past as a passionate educator, and TJ rushing off to spend the rest of the summer with his friends, not to mention Prickley THANKING TJ for dragging him into the whole mess in the first place.
Prickley See, I didnt get into teaching for the promotions or the pension plans, or to get to the golf course by 3:45. I... did it because I wanted to help you kids. I'd forgotten that... until today.
This piece of Fridge Logic (Or Fridge Horror): Because Gus has to move from town-to-town all the time (his dad's in the military), he's eventually going to leave the town the show is set in, and leave the best friends he's had in his life. It's heartbreaking when you think about it.
Although they're (usually) antagonists, Ashley A. getting kicked out of the Ashleys in "Outcast Ashley" is sad in a way. These girls have been friends since preschool, and were kicking out their best friend just for forgetting to wear purple on the anniversary of the day they met. She might've done some bad things in the past (And in future episodes, as this was one of the early season two episodes), but you can't help but feel sorta bad for Ashley A. The part where they rip her 'A' necklace off and stomp on it, and then tear the head off her teddybear backpack is especially harsh.
"Speedy, We Hardly Knew Ye". The gang return after the weekend to see that the class hamster, Speedy, has died, and get all the kids to have a funeral for Speedy. Later, the high school football team, the bus driver, and even the mayor arrive at the funeral, because they also had Speedy as their class pet. It's then revealed that every time Speedy dies, he (and in some cases, she) is replaced with a new hamster without anyone knowing. Everyone's upset because they realize that the Speedy who just died wasn't the Speedy they remember, so T.J. gives them a speech on how it doesn't matter which Speedy belonged to who; it was that Speedy was always a great friend to them.
Gelman's bullying towards Gus in "Gus's Last Stand". Especially hard for someone who's been bullied heavily.
Spinelli getting bullied endlessly in "Mama's Girl" after accidentally calling Miss Grotke "mama". It starts out somewhat humorous, but it gets to the point where she's afraid to go to school because of the bullying.
And Miss Grotke's speech about how bullying can really hurt someone, though the tears that flow will be of the "Amen to that" variety (if such a thing exists).
In "More Like Gretchen", after Spinelli's parents compare Spinelli to Gretchen, Spinelli is so upset that the next day after Gretchen came over her house, she tells Gretchen that she doesn't want to be friends with her anymore. And Gretchen didn't even know what she was doing wrong—she was just being herself.
In "Weekend at Muriel's", we have Ms. Finster's reaction to overhearing Spinelli call her "boring".
When the end credits roll.....and you realize that the episode you finished was the last episode out of the entire series. Knowing that series like this has ended will make more than a few people cry. Especially poignant knowing that this is one of the few series that has both an adult and child fanbase, because it's just so damn GOOD!
Just the thought of what would have happened had the gang been split up after the breaking of that statue. Spinelli and Vince would have let their more negative traits get the best of them without TJ to balance them out, Gretchen would have skipped out elementary, middle and maybe even high school and had no friends and Mikey and Gus might not even have survived until high school. Only TJ would have made it out okay...and that's almost worse!