Has there been any other Grey's Anatomy character who has as many mixed reviews as Derek Shepherd (Patrick Dempsey)? From season one to ten, Derek was Grey-Sloan's Chief of Neurosurgery. Not only was he married to Meredith Grey (Ellen Pompeo), but he was also close friends with Mark Sloan (Eric Dane) and Callie Torres (Sara Ramirez).

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Would fans consider him to be a great friend? Yes... and also no. Derek would step up when needed, but the neurosurgeon's ambitions would sometimes cause conflicts among many of his friends because they felt he was selfish. Would you like more examples? Keep reading to find out five reasons why Derek was a bad friend and five times he was a good one.

BAD: Degrading Meredith

Meredith and Derek in an elevator in Grey's Anatomy

After Derek reconciled with Addison (Kate Walsh), he and Meredith reached an impasse. They decided to become friends since Meredith was going through a rough patch with George (T.R. Knight) and Izzie (Katherine Heigl). However, this 'friendship' also became strained when Meredith began dating the veterinarian, Finn (Chris O'Donnell).

Derek's jealousy got the best of him once again when he realized Meredith had slept with Finn. The neuro and general surgeons come to blows when Derek shames her for sleeping with George and Finn. Meredith is furious with Derek's behavior and accuses him of breaking her in the first place. In response, Derek calls time on their friendship.

GOOD: Calming Meredith's panic attack

Derek may not have reacted in the best way when it came to Meredith, but he did prove to be a good friend when he spots her having a panic attack. In the episode "Break on Through," Meredith is shown to run into a supply closet after her patient dies. When Derek follows her in, he realizes she is panicking over the thought of her mother dying alone.

Derek then proceeds to sit with her, coaching her through her anxiety to calm her down. He waits patiently until she confirms that she feels okay to return to work. Their impasse may not have lasted long, but it was one of the nicer moments in their so-called friendship.

BAD: Fighting with Mark

One of the worst moments in Mark and Derek's friendship was when the neurosurgeon punched him. At the beginning of season 5, Derek had warned the plastics attending to stay away from Lexie (Chyler Leigh) at the request of Meredith. Unbeknownst to him, Mark and Lexie had begun to have a relationship - which Meredith knew about (as shown in a deleted scene).

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When Lexie gave Mark an ultimatum, the plastics surgeon decided to confess his relationship to Derek. As expected, Derek didn't take the news very well and got into a fight with his best friend. The neurosurgeon didn't take this betrayal likely, holding a grudge against his best friend for weeks after.

GOOD: Cristina's PTSD

One of the best moments for Derek was when he stepped up to help Cristina. After the events of the Season 6 finale, several of the doctors were seen to be traumatized- including Cristina. For a brief period, the cardiothoracic surgeon lost interest in all types of surgery. Derek tried to rejuvenate her passion but had to come up with another plan when that didn't work.

The neurosurgeon decides to take Cristina on a fishing trip to try and take her mind off it all. Surprisingly, the trip seems to be the thing she needed the most as this was the first thing she had succeeded in since the shooting. Derek was pleased to see her crying because it allowed him to see Cristina was beginning to heal.

BAD: Lack of support for Mark

Mark Sloan on Grey's Anatomy

One thing that was bothersome about Mark and Derek's relationship was the fact that it looked one-sided. Considering the childhood best friends feel they are like brothers, Derek wasn't there for Mark as much as he was for him.

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For instance, where was the neurosurgeon when Lexie broke up with Mark for the first time? Or when Mark debated settling down with Julia (Holley Fain)? Mark was lucky that he had Callie and Arizona (Jessica Capshaw) supporting him because he was confused through it all. Mark was constantly there for Derek when he was going through a rough patch with Meredith, so why didn't he share the same courtesy?

GOOD: Friend during Callie's crash

An image of Callie smiling in Grey's Anatomy

The only supportive thing Derek ever did for Mark was request somebody go after him after Callie's car crash. In the episode "Song Beneath the Song", Derek was forced to operate on Callie after her injuries were extensive. Callie had also been pregnant with Sofia, which meant Mark could lose his best friend and daughter.

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When Derek notices Arizona sitting in the gallery, he asks somebody to go find Mark. He probably would have sat with the plastics surgeon if he wasn't in surgery and Lexie wasn't there to keep him company.

BAD: Richard's alcoholism

One of the worst moments in Grey's Anatomy was when Derek exploited Richard's illness. In the episode "New History," Richard (James Pickens Jr.) was shown to relapse after the stress of the job and his other responsibilities begin to take its toll.

Derek had made no secret that he was after the Chief's job. Instead of supporting Richard through this tough time, Derek used this opportunity to expose the General surgeon's illness, knowing he would be able to become interim Chief. Even Meredith believed he was crossing the line, knowing his motives were self-interested. He confirmed her suspicions when he tried to bribe her into giving Richard up for Izzie (Katherine Heigl).

GOOD: Comforting Lexie

Lexie Grey reacts to news about her father's death in Grey's Anatomy

They may not have started off close, but Meredith's relationship led to a bond forming between Derek and Lexie. In season 8, Derek began to train Lexie as his resident; their relationship also became closer when Lexie began to confide in him about Mark.

Although he was hesitant to get involved at first, Derek quickly grew into the big brother role. He would often provide comfort to the youngest Grey, giving her advice on her situation and encouraging her career. Derek's best moments came in "Moment of Truth" and "Let the Bad Times Roll" when he consoled Lexie after she expressed her frustration of not telling Mark about her feelings.

BAD: Exploits his friends

Derek leaning against a wall on Grey's Anatomy

Another aspect many fans didn't like was how Derek would exploit his friends. Derek seemed more than willing to accept the help of others, but would never return the favor. For instance, the closest friends he ever had on the show were Mark and Owen. However, he somehow managed to recruit Jackson (Jesse Williams), Alex (Justin Chambers) and Ben (Jason George) into helping to create his deck (in the episode "What Is It About Men").

He also exploits Callie in "Throwing it All Away," wanting to remove her off their project after the President takes an interest in his work. Meredith was right when she said he believed his career was more important than everyone else's.

GOOD: He's At Mark's bedside when he dies

Derek and Mark walking in the hospital in Grey's Anatomy.

He may not have shown his appreciation as much as Mark did, but Derek's presence at his bedside proved how much he loved his friend. In season 9, fans were shocked to discover their favorite plastics attending was about to be taken off life support after falling into a coma ("Going Gone Gone"). This was all at the wishes of Mark, who requested his friends that he be taken off the machine if there were no signs of recovery.

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Both Callie and Derek were seen to struggle with the thought of losing their friend, using surgery to distract themselves. When the time comes, the pair refuse to leave his bedside until he finally passes. For the majority of season 9, fans see how much Mark's death affected him.

NEXT: Grey's Anatomy: 5 Times Meredith Grey Was A Genius (& 5 Times She Wasn't)