Meredith Grey is the surgeon extraordinaire and central protagonist of the long-running ABC medical drama Grey's Anatomy. The series recently kicked off its seventeenth season with a two-hour season premiere revolving around the current global crisis.

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Meredith has evolved tremendously over the years into a mature, brilliant doctor and a widow with three kids, but there were times in the show when she behaved in a particularly frustrating manner. At other times, though, she was extremely sweet and decent.

Annoying: Used & Hurt George

George confesses to Meredith that he loves her

George O'Malley was one of the most adorable characters, who lasted only a few seasons before he met a shockingly tragic end. Now, one of the primary storylines involving George in the early seasons was his huge crush on Meredith, which he hid pretty well from her for a while.

But when Meredith finally agreed to be with him, she messed it up badly. Firstly, she had only agreed to sleep with George to take her mind off things; she never intended for it to be serious, in spite of knowing very well that he had feelings for her, which was rather mean. Secondly, she started crying while they were in bed together, thus humiliating George. Hurting fan-favorite George like that was definitely not fun.

Sweetest: Gave Part Of Her Liver To Her Estranged Dad

Meredith with Thatcher Grey

Meredith had never really known her dad, who abandoned her mother and her when she was still young. True, it was her mother Ellis who had cheated on him first, but Meredith always blamed her dad for letting her go easy.

However, in spite of the strained relationship she had with Thatcher Grey, Meredith agreed to donate a part of her liver when Thatcher's life was in danger and she herself was the only match. Of course, this was a matter of life and death, but it was still sweet of her to help save her dad.

Annoying: Behaved Atrociously With Lexie

Lexie and Meredith talking at the hospital on Grey's Anatomy

Another annoying thing Meredith did besides hurting George was the way she behaved with her half-sister Lexie Grey. Lexie ed Seattle Grace as a surgical intern and was a sweet, gentle young girl who wanted to initiate a relationship with Meredith.

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However, Meredith's initial reaction to Lexie was quite atrocious; she kept snubbing her and giving her the cold shoulder even though Lexie had done absolutely nothing to deserve such coldness. It was positively annoying to Meredith's treatment of such a genuinely good person.

Sweetest: Gave Cristina Her Sparkle Pager

Meredith and Cristina discuss their love lives at Meredith's house

When Miranda Bailey thrust her residents and interns into the midst of a surgical competition, things heated up as each resident tried to one-up the other so that they could walk away with all the glory.

Meredith came out on top of the competition, and Bailey gave her a special sparkle pager which gave her the right to snatch away any surgery she liked from anyone who paged her. But Cristina, who had by then become firm friends with Meredith, was still trying to settle back into surgery after being left at the altar by Preston Burke and to cheer her up, Meredith readily parted with her prize, which was the sparkle pager.

Annoying: Kidnapped Zola

Baby Zola and Meredith Grey's

Meredith was particularly annoying when she decided to take off with baby Zola at the same time that she had tampered with Derek's clinical trial, and been just fired from the hospital for her transgression. Her spur of the moment decision could have cost her and Derek the chance to legally adopt their baby.

Meredith disappeared with Zola even though she was well aware that any questionable behavior on the part of the prospective parents would raise doubts regarding their suitability to adopt a child. It seemed utterly thoughtless of her and was profoundly annoying, both to Derek and others involved and to the fans.

Sweetest: Set Up Izzie & Alex's Wedding

Alex And Izzie Wedding

When Meredith and Derek were unwillingly getting ready for their social wedding--unwilling because neither of them wanted a big white wedding--Izzie had been diagnosed with cancer and was going through surgery.

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Since Izzie had always dreamed of a big wedding unlike Meredith, the latter, along with Derek, had a brainwave wherein they arranged for Izzie and Alex to get married in the same church that had been booked for their wedding. It was an uncommonly decent, sweet gesture on their part for a dying friend.

Annoying: Destroyed Derek's Clinical Trial

Ellen Pompeo as Meredith Grey tampering with the Alzheimer's trial in Grey's Anatomy

Fans are aware that Meredith tampered with the clinical trial that Derek was conducting along with her to find a cure for Alzheimer's disease.

Now, the steps she took were motivated by her feelings for Richard, who was the only father figure in her life; she wanted his wife Adele to get the Alzheimer's medication instead of the placebo, and had changed the envelopes that would determine the medication with that purpose. However, even though her actions were well-meant, she still knowingly risked her own as well as Derek's career and reputation which was frustrating, to say the least.

Sweetest: Set Up The Dream Proposal

Meredith House Of Candles

For all her annoying ways, there was no doubt that Meredith was head over heels in love with Derek, and would have been willing to go to any lengths for him.

She set up the most romantic, beautiful ambiance to propose to Derek, by building him a house of candles at the exact spot on the hilltop where Derek owned a plot of land and hoped to build his dream house. Although the proposal never ended up happening, the gesture was amazing.

Annoying: Tried To Talk Owen Off Cristina

Meredith Grey and Owen Hunt

Meredith's behavior was seriously annoying when she tried to somehow talk Owen Hunt, the trauma surgeon, off marrying and being with Cristina.

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True, Cristina had suffered a heartbreak already, and as her 'person', Meredith had every right to look out for her. But when Owen had so clearly pledged himself to Cristina, for Meredith to constantly question that and wonder whether their marriage was a good idea, seemed like unnecessary interference in other people's business.

Sweetest:  Agreed To Leave Seattle For Derek

meredith and derek on grey's anatomy

One of the sweetest things Meredith did was for the love of her life, the brilliant neurosurgeon Derek Shepherd.

Derek was offered an important position to head a medical by the White House in Washington DC and became adamant about accepting the offer after initially refusing it. And even though her entire life and career were in Seattle, Meredith agreed to give up everything and travel with Derek to start over in DC. Although she changed her mind later on, she was willing to give up all that was familiar to her for the sake of her husband.

NEXT: Grey's Anatomy: 5 Times Meredith And Derek Were The Perfect Couple (& 5 Times They Weren't)