Between the patients,  doctors, nurses, and janitors, (not to mention the friends and family that are inexplicably allowed to accompany JD to work),  the Scrubs audience has no shortage of great characters to leave an impact. While some of these characters grew and developed from season to season, others had to make their mark in a much shorter time; a single episode.

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These characters may not have been around for long, but the impact they left on Scrubs and its main characters is much more lasting.

Mrs. Tanner- Season 1, Episode 4

Mrs Tanner looking sad in Scrubs

Mrs. Tanner is a likable old woman that JD befriends in his first year at Sacred Heart. With her spunky attitude and grandmotherly demeanor, it is difficult for JD to accept when she decides not to continue treatment and instead embraces her imminent death.

As a young medical intern, this is an important lesson for JD; not every patient can be saved, nor do they all want to be. Death is a common theme of the show, and JD will continue to struggle with the concept in every season. Mrs. Tanner is memorable for her wisdom and helps JD herself in accepting her death. In future heartbreaking episodes when JD is faced with other patients that he cannot save, he is able to be there for them instead

Nick Murdock- Season 1, Episode 7

DJ and Nick Murdock posing together in Scrubs

Nick is a fellow medical intern in season 1, working beside JD and Elliot. He's regarded as extremely talented, warranting praise from both Dr. Cox and Dr. Kelso. This leads JD to become jealous until Nick suddenly quits after the emotional pressures of the job get to him.

Up to this point in the show, JD put all of his focus into the book smarts that he needed in order to be the doctor with all the right answers. Through Nick, JD learns that without a balance between empathy and a tough skin, all the knowledge in the world is useless. This balance became a theme for many future episodes, and Nick's example started JD on his journey to the doctor that he would become.

Elaine- Season 2, Episode 13

Elaine looking into the distance in Scrubs

While many patients on the show, Elaine is one of the most memorable due to her flashy musical exit. Through one of JDs classic daydreams, the scene of Elaine crashing is replaced with her performing the song 'Waiting for My Real Life to Begin' in a sparkly red gown.

While JD's fantasies are typically of a comic nature, his fantasy of Elaine ing on was emotional and poetic to viewers. The episode's theme was life balancing life, and when JD was able to save a different patient, he had to face the disappointment of losing Elaine. While viewers didn't know Elaine long, her presence on the show was one of the first examples of Scrubs' ability to balance comedy with truly heart-crushing moments.

Dr. Townshend- Season 2, Episode 14

JD and Dr Townshend smiling in Scrubs

Townshend is a jovial, extremely likable old colleague of Dr. Kelso's.  Kind, energetic, intelligent, and funny, the seasoned doctor was liked by everyone. This made it all the more difficult for JD to report his outdated and dangerous medical practices to Dr. Kelso.

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When Kelso originally reprimands JD for throwing his old friend under the bus, viewers were unsurprised. However, when Kelso privately confronts Townshend and fires him, audiences are able to see evidence of integrity in Kelso that he is not typically known for. Kelso put the safety of patients ahead of his relationship with an old friend. While Townshend didn't end up being the friendly mentor that JD had been craving, his brief presence gave audiences the first hint that Kelso's ruthlessness was not simply part of his personality, but a result of the challenges from his position as Chief of Medicine.

Spence- Season 2, Episode 22

JD, Turk, and Spence at a hot tub in Scrubs

When Turk and JD are beginning to feel that their careers are considerably less glamorous than they had expected back in the day, an old college buddy by the name of Spence comes to visit. JD and Turk blow off work to go out drinking with Spence, and JD receives a good old-fashioned Dr. Cox lecture, followed by a lecture from Spence himself.

While Spence heads home at the end of this episode, never to return, his visit reminded JD and Turk that they must make sacrifices if they want to continue helping people. The show often shows that being a doctor isn't always saving young lives with big dramatic diagnoses. Even the boring and disgusting work is important. JD and Terk needed their old friend to help align their past dreams with their current reality, and come to with what is actually important: the people they help.

Denise Lemmon- Season 4, Episode 8

Denise sticking her head out an ambulance window and smiling in Scrubs

When Dr. Cox has to perform public service hours in order to return to work at the hospital, he is put to work with an extremely optimistic EMT named Denise. Dr. Cox considers this to be his own personal hell but has no choice but to listen to the woman talk energetically about anything that comes to her mind, especially her 10-year-old son.

What started as an entertaining episode of Dr. Cox spending time with his antithesis, quickly changed to a heartbreaking story of love and loss when Dr. Cox discovers that the son she goes on about actually ed away years ago. Though by season 4 it is no surprise to audiences when Dr. Cox shows his gentler side, what makes Denise difficult to forget is her truly tragic story and the optimism with which she sees life.  Her line "he will always be this age to me" takes on a whole new meaning after Cox's discovery, stirring emotion in viewers, as well as in Dr. Cox.

Murray Marks- Season 4, Episode 11

Murray Marks standing next to his father in Scrubs

Murray Marks is the son of one of JD's patients, Gregory, that refuses to give his father a kidney until he learns that Gregory is not actually his biological father. Murray felt that Gregory was never there for him, but the knowledge that his father knew the truth but still treated him as a son changes his perspective.

This complicated father-son relationship is paralleled to the relationship between JD and Dr. Cox. Through observing this, Dr. Cox realizes just how much JD internalizes his opinions, and JD realizes that Dr. Cox is hard on him in an effort to help him grow. While their relationship is far from perfect, Seeing Murray and his father helps the two of them develop into the mentor, mentee relationship that viewers love to watch.

Billy Callahan- Season 4, Episode 14

Bill Callahan kissing Elliot in Scrubs

When JD and Terk meet Billy Callahan, they are stuck in the rut of working and returning home to do virtually nothing. This is greatly contrasted by the character Billy, whose spontaneous and adventurous lifestyle (and possibly his devilish good looks), attracts many of the hospital staff.

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While at the hospital, Billy inspires everyone to live a little more and think a little less. JD needs to be reminded of this many a time more but Billy serves as the most memorable reminder before he walks off into the sunset, never to be seen on the show again. The need to balance work and life is a frequent theme of the show, and Billy's contrasting example of kindness and chaos seems to be one that could resonate with Scrubs' complicated characters.

Paige Cox- Season 5, Episode 5

Dr- Cox and Paige in Scrubs

Dr. Cox is revealed early in the show to not be as big and bad as he would like people to believe. Beneath his tough exterior is an emotional softy that audiences love to see exposed.

One example of this is when his sister Paige, comes to visit. As the only direct family member of Cox's that the audience meets, she is already fairly notable. However, Paige is memorable due to her contrast with her brother. She is kind, gentle, and a born-again Christian; showcasing the way that trauma, in this case taking the form of the siblings' abusive father, can lead people onto different paths. Ultimately, the two learn to tolerate each other, and Paige never appears again. However, Paige served to expose yet another layer of the complex character of Dr. Cox.

George Valentine- Season 8, Episode 2

George Valentine lying in a hospital bed in Scrubs

George Valentine is another patient treated by JD that is doomed not to survive. While this outcome is not unique to the show, George is one of the last patients of this type that viewers meet.

JD is shown, through his experience with George, to still struggle with death, despite being exposed to it for so long. When George asks for reassurance about the painlessness of death, JD is forced to face some of his own fears in order to be there for George. Taking place in the final season of the show, JD's ability to comfort George as he es away contrasts with his difficulty in Season 1 with letting Mrs. Tanner go. While audiences learn little about George, they are affected by the emotional moment, both for his sad story and for the evidence of JD's growth as the protagonist of the show.

NEXT: What Your Favorite Scrubs Character Says About You