Elsie's meltdown in her elimination episode. She was getting bogged down from the stress which was made even worse when Jessica, Michael and Ralph refused to help her.
Season 2
Larry's withdrawal due to illness. It was the first elimination for medical reasons in the show's history, and it's hard to watch Larry talk about how he's losing his chance at his dream due to reasons outside of his control.
Larry: I didn't quit. My body quit.
Rachel's run after Heather was assigned to the Blue Team is heartbreaking as well. She began to struggle more, and tended to put herself down a lot more. One moment in particular that stands out as after she gets ice after barely managing to convince the other customers to pay for it, she ends up tripping and breaking one of the bags.
Season 3
Aaron's withdrawal. When he gets the call that he can't come back into Hell's Kitchen, he just replies with a defeated "okay".
Episode 9. The episode before, Julia was eliminated and Ramsay had promised her she's off to culinary school. What's going on with everyone else? Bonnie is heartbroken that she had to put up her close friend to be eliminated and is hugging Jen. Rock? He's sitting alone, hitting his head with a fist in dismay because Julia was such a Worthy Opponent to him.
Her meltdown on the garnish station also qualifies. After Ramsay accused Julia of no longer trying after she forgot the garnish for the monkfish, she's trying to convince herself to keep going and to not give up. Seeing Julia crying both during the service and during the confessionals when she's calling herself "stupid" for her mistakes is heartbreaking because the audience wants her to succeed and to prove Tiffany and Joanna wrong but she just can't.
The end of that episode is also heartbreaking as Ramsay sadly stated that Julia was eliminated and how he promised to send her to culinary school, hoping that she would come back one day to win the competition hands down.
Not only that, but unlike seasons before and even future seasons, Gordon seemed genuinely reluctant to eliminate Julia over Rock, who was also a favorite. You can even tell how much this hurts him as he has to apologize for the decision.
And twisting the elimination further, just rewatch Julia's expression as she is announced the winner of the first Black Jackets Challenge, having struggled with Tiffany and Joanna's bullying in the first service and her struggles to keep up with her more formally trained competitors... and then remember that she's going to be eliminated at the end of that episode.
Julia: I made it really far, but I don't wanna go home.
Speaking of Episode 9, Josh's mid-service elimination can be sad according to some. During his elimination speech, while he isn't seen crying, his heavy breaths indicate he's on the verge of tears.
Season 4
Episode 2. Petrozza almost losing all will to fight after he was twice sent back up to the dorms to study that evening's dessert menu. Feeling his spirit beaten down by Ramsay's chastising, he was so ashamed of his carelessness that he said he was ready to throw in the towel. Thankfully, Bobby rushes in and gets his spirits back up, and with a little motivation Petrozza was back to his old self. Still, watching such a genuine guy feel so deflated for having made an honest mistake is pretty tough to watch.
Episode 5. After burning her hand on a hot grease-filled pan in the previous episode, Vanessa was forced to quit the competition for she felt that she could not perform up to the kitchen's intense standard with only one hand. Ramsay lamented that the circumstances had forced her to leave, and even Jen of all people was hugging Vanessa as she announced her decision to leave to her entire team. Shayna felt that Vanessa had given up on herself too early. What makes it all the more bittersweet is that if Vanessa had continued competing, her injury would almost certainly have resulted in far more lasting damage than had already been dealt.
Season 5
Robert withdrawing from the competition due to health problems. As one of the most passionate chefs that season, he worked so hard and fought his way to the Final Five, only for him to get his dream taken from him by a heart condition. Right in the middle of seeing the prize restaurant. To add to it, Robert cancelled his wedding just to compete.
Especially saddening is when he returns to the restaurant in person to a standing ovation from Ramsay and the remaining contestants, in full uniform and seemingly back to his old self. When he reveals he's still not well and must withdraw, everybody's hearts just sink.
Ji's withdrawal in Episode 2 due to an accident where she sprained her ankle. Her teammates were all crying (and some of the men even appeared to be on the verge of it) because they felt she was a strong competitor even with her injury.
Danny may have come across as a bit arrogant at times. His final confessional, after winning the season, shows him crying and saying that he knows that his late mother is smiling down at him proud.
Season 7
Nilka's ejection as a whole. After repeatedly messing up, Ramsay is finally fed up enough to force her out, but she refuses to give up to the point that she becomes a detriment to the work of the remaining chefs. Compounded by Ramsay's tonal reversal when he personally wishes her well as she truly leaves the studio.
Season 8
Curtis's elimination is heartbreaking. While he was The Load on service that night, he was not only not nominated for elimination, but was put on a station that he knew he was weak on, as shown during the sushi challenge earlier, where he produced no acceptable suishi. His exit interview sees him absolutely crushed and tearing up, apologizing for letting his family down.
To make matters worse, teammate Rob had multiple chances to slide over and help during service, but unlike other contestants like Petrozza or Ariel, who were at least nice enough to assist their teammates in an area they were weak (Petrozza assisting Louross with the meat by slicing the sliver off to make it presentable to Sous Chef Scott in Season 4, and Ariel assisting Kanae with tasting the prawn dish during the Chinese Cusine Challenge in Season 18 due to the latter's allergy to nuts that were required for her dish), despite knowing Curtis was struggling with sushi and got the kitchen off to a bad start, he intentionally refused to help him and relished in watching him sink.
Season 9
In Episode 11, after another poor performance from the Blue Team, they are forced to nominate someone. At this point in the competition, the remaining four on the Blue Team in Paul, Will, Tommy, and Natalie were all very close with each other. Even after Natalie is decided on as the nominee, they're all very reluctant to send her up, and even comfort her. Sure enough, she's sent up alongside Elise, and Natalie is eliminated.
Paul revealing that he was on Hell's Kitchen for his mother, who apparently died not long before he was on the show. Watch the finale, and try not to cry when he wins.
Season 10
Roshni's elimination. Seeing her fighting for her chance to remain in the competition by reminding the guys on the blue team that in a previous service she and Brian were the only ones to complete the dinner service while the rest of them got kicked out of the kitchen and the guys saying they thought Patrick was better than her is a major tearjerker.
Season 11
The Finale. When it was revealed that Ja'Nel was the winner, Mary is crying because while she wants to be happy for Ja'Nel's success, it's a bitter pill to swallow. To twist this moment even further, Dan (who was acting like a total jerk throughout prep and who slowed down dinner service to the point that Mary had to kick him out) goes to Mary and hugs her, apologizes for his behavior and promises to make it up to her someday. Question, Dan: Where was that kind side of you throughout the season?! Made even worse by the fact that Ja'Nel didn't even end up getting the job due to her failing a drug test, leading many to argue that Mary should've won instead.
And speaking of Dan, his elimination can be a bit sad, depending on one's view. During his elimination speech, as he was calling out his teammates for bullying him over the course of his run in the competition, you can hear small cracks in his voice as if he was trying to hold back tears.
Season 12
In a way, Simone's leaving Hell's Kitchen at the end of Episode 3. Whether she was faking illness or not is still up to speculation, but she sounds so defeated and just says "It's OK, Chef, I can go" instead of giving Chef Ramsay a chance to announce who is leaving.
Jessica's elimination. After losing the "Cook For Your Life" challenge to Richard, she has a complete mental breakdown and begs not be kicked-off the show. Even with her mistakes, it's really hard to watch and not feel sorry for her. Even Sandra of all people said she felt bad for her.
Rochelle's breakdown in Episode 13. After being tasked with creating a menu for the coming Red vs. Blue menu dinner service, Rochelle became uncharacteristically quiet during the menu creation process and struggled to come up with ideas, which was caused by her lack of experience working in a fine dining restaurant. When it came time to showcase the demo dishes, the crab cake that she made was burnt underneath and she let out a nervous laugh during the critique, which Chef Ramsay berates her for. Then, hours before the doors opened, Rochelle's frustration reached its peak and she broke down in tears, to the point where she considered throwing in the towel. After seeing her be all optimistic and cheerful throughout the season up until this point, seeing Rochelle so down on herself was rather difficult to watch. Luckily, after having a short talk with Kashia, Rochelle quickly rebounded and delivered a strong performance at dinner service.
Joy's quitting. While she was a very divisive chef during her run, and her quitting soured fans on her, her realizing that she just threw away her chances at winning and not having the confidence to go back in and ask for a second chance really hurts.
Season 13
Ashley's elimination. Throughout the season, she remained blank-faced and emotionless, but in the interview afterwards, she's seen crying, saying all she wanted was to work with Chef Ramsay and that it really hurts knowing he thought she wasn't good enough. It's made worse since she arguably didn't deserve to be eliminated (Roe and Steve were up for the second time in a row).
Episode 9: Steve is forced out of the competition due to a leg injury. Ramsay even expressed disappointment, as he felt that Steve had been a solid competitor throughout the season. What makes it worse is that Steve clearly wanted to go on, but Chef Ramsay said he couldn't let Steve sacrifice his health for the show.
Frank's elimination, too, for that matter. He takes it gracefully, but is visibly holding back tears and is very upset with himself. It's made even worse since he wrote Chef Ramsay a thank-you note earlier that episode for not eliminating him the previous night (which is sort of happy-tear-jerking, since Ramsay expresses gratitude for it).
Season 14
Bret suffered a fate almost identical to Steve's the previous season, being removed from the competition due to a slipped disc in his back by Chef Ramsay, despite being considered one of the best (if not THE best) chefs on the blue team.
Luckily, with Season 18 (Rookies vs. Veterans), Bret finally got another shot at the title, and despite yet another health scare, this time he made it all the way to third place.
It becomes much more bittersweet when you learn that Bret's parents both passed away within mere months of each other since his last appearance, and has their names tattooed on his wrists in honor of their memory. He explains to Season 4's Jen, whom he got off to a bad start with just how much cooking means to him and his family and how cooking was a passion he shared with both of his parents and thus motivates him that much more in his second run on the show. Jen visibly tears up after hearing his story.
Season 16
The Blue Team teaming up to bully various members of the Red Team in hopes the stress would lead to them messing up and getting eliminated, and outright bragging about who they plan to go after next.
Paulie meeting up with his parents. While he isn't the most well-liked contestant on the show, knowing that he would pass away only a few months after the episode aired really hurts.
Season 17 (All Stars)
Ben (previously on Season 5, not to be confused with Benjamin previously on Season 7) reveals that he had been diagnosed with diabetes, and nearly falls on the floor during the first dinner service until Jared catches him. He gets eliminated that night even though the Blue Team won the service, with Chef Ramsay suggesting that his health could be a liability further down the competition. Give Ben credit for stating in his exit interview that he felt it was the right decision.
Robyn and Jennifer tearing up during the end of the Black Jackets Challenge. It's clear that the two respect each other as chefs and did not want to see the other get eliminated.
There's also Nick's elimination, where he ends up losing solely because Mark Frissora liked Benjamin's dish a little more. Nick is a Graceful Loser about this, but it's clear from his reaction that he's barely holding back tears and anger after being eliminated in a situation Gordon had no say in.
Season 18 (Rookies Vs. Veterans)
While it is played for laughs, the removal of the lobster risotto can be sad to long-time fans of the show, especially since that risotto was there since the beginning.
Chris's departure. He already revealed in the beginning that he suffered a massive accident to the head that caused him trauma, and was starting to go back into a dark place he once was in nine months ago. Not even him being the key factor that helped the Red Team win the challenge was able to break that, and it led to him making the ultimate decision to walk out. When Ramsay announced it to everybody before service, you can see how shocked and saddened they were by that news.
Alex is billed as a former restaurant owner. When prompted by Gordon during the Signature Dish Challenge, he elaborates that he opened it in 2018, but was forced to close just two years later because of the COVID-19 Pandemic. Ouch. This makes it all the sweeter when he wins.
The Black Jackets' first night together has them sharing their experiences during the pandemic, showing how it negatively affected their lives. Cheyenne was at college when it happened, and she was sent her belongings back along with the others at her school after an announcement of a two-week break. Alejandro and Dafne had their workplaces shut down and lost their jobs. While Alex mentioned at the beginning of the season that he closed his own restaurant after two years, he remembers how scary it was as he struggled to provide for his family, then he reveals he sold it two days before coming to Los Angeles.
as a whole. After repeatedly messing up, Ramsay is finally fed up enough to force her out, but she refuses to give up to the point that she becomes a detriment to the work of the remaining chefs. Compounded by Ramsay's tonal reversal when he personally wishes her well as she truly leaves the studio.