In iGot a Hot Room, Carly's room burns down due to the gummy bear lamp Spencer made for her. The only time the Epic Fail trope is played for something serious on the show. It's tearjerking because Carly was really upset, and a lot of her things were destroyed.
The look on Spencer's face when he realises the fire is his fault, Sam and Freddie's emotion in their voices, and the music playing make that scene one giant Tear Jerker.
Freddie in iSaved Your Life. The couple looked so happy and cute together, and then Sam gets into his head with the bacon theory. You can tell he's not comfortable with the situation at all, and that even kissing Carly feels like he's doing the wrong thing. The way he 'retreats', and then his "What did I do" introspection. That whole episode cemented both Freddie's woobie status, as he just cannot catch a break (even from his own conscience), and cemented just how strong his convictions are. But still, poor guy.
The scene with Sam in juvie
Carly's breakdown when she realizes that she misses her old life and wants things back the way they were. Her crying in the hallway was a true Tear Jerker.
The last half in one way or another.
iQuit iCarly. The near death experience Carly has on the window washer's platform, being saved by Sam, Spencer and Freddie, and realizing what they've been through in the episode...their reaction says it all.
And then they're so frightened and in shock after that near death experience that they just turn to each other and start sobbing and hugging each other.
iPsycho: When Gibby is sad about being too old to go camping, he mentions that one of the things he'll do in the meantime is watch reruns of Different Strokes. Note that this episode aired exactly a week after Gary Coleman's passing and even the audience track seemed more real at that moment as how everyone felt about his passing.
iDo: Carly singing her song Shakespeare to Jodi after Gordon finds himself unable to.
iPity the Nevel. No intervention of lame background jokes, not even the bad-punchline conclusion of that episode, can take away the power of suddenly finding a guilty conscience in Nevel ... and especially seeing the heartfelt, truly emotional reconciliation between Nevel and the little girl he had spazzed on..
Freddie's speech to Sam at the end of iOMG.
And her subsequent reaction.
Carly having her heart broken by Steven in iParty With Victorious.
iWanna Stay With Spencer: Carly and Spencer's farewell. And the when the whole Carly going away thing gets cancelled, as Grandpa Shay sees how much Spencer cares about Carly.
In iCook, this small scene happens.
Spencer: Sorry, I was just... waiting for someone.
Spencer: Nothing, it was stupid... I'm gonna... I'll just... Goodnight.
Which brings tears of joy when Nug-Nug shows up and he and Spencer hug.
In iParty With Victorious:
(After it is revealed that Steven is cheating on Carly.)
iLove You. Carly tells Spencer and Jenna that their relationship isn't normal. We then see that Sam and Freddie are eavesdropping on the conversation. Carly tells Jenna and Spencer that they are taking the platonic connection they have and trying to force it into a relationship and that it's weird. Sam and Freddie get in the elevator, and Sam stops it to ask Freddie if she thinks they doing the same thing as Jenna and Spencer. Sam thinks the kiss was "just intense" claiming the two don't click that way. Then they talk about how each other is not suited for the other. Freddie is too normal for Sam, and Sam is too abnormal for Freddie. They then realize they have broken up. Sam then un-pauses the elevator and it lands in the apartment, where Freddie tells Sam he loves her. There's a beat. Then Sam says the same. And they kiss. They then decide to break up at midnight because it's only 10:30. And the episode ends as they kiss again before the elevator closes.
iStill Psycho, having no other means of escape, the iCarly gang shock Freddie to disable to tracking chip in his head to trigger an alarm to get Mrs. Benson to come save them. Mrs. Benson is absolutely terrified when she gets the alarm, scared that the Ax-Crazy Nora may have done something to Freddie. Adult Fear is in full gear for this.
Spencer and Sam in this episode is a non-stop tearjerker, culminating with the moment Spencer tells Sam about how great she is, and gives her the bike that they spent their time working on.
Fridge tearjerker when you watch #Yay Day in Sam & Cat and you realize Sam has never had a good gift from anyone. Although Jennette Mc Curdy had filmed that episode for her show over a year later, her reaction in this episode to getting the motorcycle fits very well with what we find out about her in the future.
Carly goes up to the studio, knowing she's leaving for Italy soon. After realizing her feelings for Freddie, she places her hand on his, stopping him in his tracks. Carly kisses him and Freddie returns the kiss.
The entire episode, especially the last few minutes where Carly sits on the plane, about to leave for Italy, watching the very first iCarly stream, and Spencer, Freddie and Sam all thinking back on how they all started iCarly in the first place. ESPECIALLY the moment right before the episode ends, with an overlay of Freddie saying "And...we're clear."
Spencer and Carly's final interaction. Might not mean much to some, but as a big brother...Well, let's take a moment and remember that this guy practically raised her. Remember all of the moments they fought and made up, and all of the quirky little moments they shared. They took care of each other. Arguably one of the sweetest brother-sister relationships on television. And when Spencer tries to say goodbye...she tells him not to, because it'd be too emotional. He does it anyway, and...well, I had trouble seeing through the flood of tears.
Fridge tearjerker when you remember how long these two have worked together.