Below is Shonda Rhimes' blog about "What a Difference a Day Makes," Thursday night's terrific episode of Grey's Anatomy. Here's what the show's creator and executive producer had to say about the events of that night and the 100th episode milestone ...

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Okay. So... 100. 100 episodes. Which means I was so tired last night that I forgot to blog. But I’m blogging now. I’m here now.

First, a warning: this is our last blog of the season. It’s also our last podcast and today will be my last tweets of the season.

We’re going dark, people.

Why? Because next week’s episodes (two in one night) are so explosive and cliff-hanger-y that we, the writers, have all agreed that we can’t even talk about them. For fear of giving anything away. We honestly can’t say a word. But know that we are proud.

Of the episodes. And of you.

For sticking with us. For 100 plus episodes. For going through the good and the bad. For having faith in us. And in our characters. We thank you and we appreciate it. There are not words to express how much we appreciate it.

So this is the last you will hear from us until next season.

What can I say about the 100th? Well, there was a wedding. Which made some of you cry and made some you mad. There was Denny. Which made some of you cry and some of you mad.

But mostly, there was a point. I had a point!

That happy woman you saw? Doing her solo surgery and smiling at the Chief?  The one giving her wedding away with warmth and joy? THAT WAS THE SAME WOMAN WHO TRIED TO DROWN HERSELF. That was our dark and twisty girl. All grown up. Whole. Healed. FOR REAL.

It was a day I never thought we’d see (well, I did think it but... hell, you know what I mean). For once, Mer is the calm one. The happy one. The one who is fine.

For once, Mer is whole and healed and happy.

She doesn’t have a problem ... well, other than the Chief peeking over her shoulder during her solo surgery. She is excited about her marriage. She is calm. She doesn’t need her eyebrows shaved off to be numbed into the submission of marriage. She is fine.

That is shocking, I think. So I’m going to say it again. SHE. IS. FINE.

That was my point. After 100 episodes, Meredith Grey is grown up. She is the thing her mother wished for her. She is extraordinary. Because, to get past the crap of your past? To move on? To let the past go and change? That is extraordinary. To love? Without fear? Without screwing it up?  That is extraordinary. It makes me happy to see her happy.

Now, Izzie’s got some problems. Her tumor is back. And she is scared to death. But the thing is, Alex has grown up too. Look at him. Standing at the altar and saying those vows like a man. He’s grown up. And the two of them are married. Which is unbearably sad because you know and I know the wedding wouldn’t be happening if it wasn’t clear that Izzie is maybe going to die. But he’s become a man who can step up. And I love him for it.

I went up to the editing room when the show was being editing and I saw my first images of Izzie lying in the hospital bed bald. And I started to cry.  And I said to Susan Vaill, our brilliant editor, I said, “Ummm ... I think Izzie is really sick.” And she hollered at me “YOU MADE HER SICK!!!!”

But here’s the thing. Until I saw my Izzie, bald and pale and wheezing in that bed…I mean, she’s sick. She’s really sick. And I didn’t see it coming.  My brain got ahead of my heart on this one. It hurt my heart to see her so sick. The magnitude of one of our own, that sick, it was shocking to see off the page and on the screen. She’s sick. She’s really sick. And now I’m a little scared.

In this episode, Denny comes back. Not as her boyfriend  Not as the guy she hallucinates having sex with. No. Denny comes back as death. Death with a capital “D”. Did you notice the black clothes?  The way he speaks sparingly? He’s death. He’s death standing over her.

I kept chanting the Emily Dickinson poem - “because I could not stop for death, he kindly stopped for me”. That’s Denny. I gotta admit, I’m crossing my fingers that he goes away. Because, as much as I love Denny (and y’all know how I love him), I want him to get out of there. Like Bailey says “YOU TELL DENNY TO GO HOME.” Because I don’t want Death to get Izzie.

Did you see George follow Owen’s advice and  go where he was needed? Right to Izzie’s side to help her down the aisle? He wasn’t the hero. He was on the team. He went where he was needed. And Lexie?  Saying “you’re breathing?” One of my favorite moments ever.

And Callie? Oh my god, do I love Callie. And I love her with Arizona, a whole healed person in her own right. There was something so painfully poignant about Callie admitting that she is broke. That the relationship is no longer on equal footing.

That she feels like she is in over her head because her father disowned her and cleaned out her bank account. I love that Arizona says “I like the girl who has the sandwiches.” I like that they make me feel hopeful about love.  Callie deserves a little happy.

Owen and Cristina are still in pain, however. I am rooting for them and you should be too. He’s a good man, that Owen. He’s good for Cristina. And, if they can get past the choking, maybe they will make it.

But I’m coming back to Mer and Der. Happy. Completely and totally happy.  Which is rare for anyone. But shocking for Meredith and Derek. They really are soul mates. And they really are perfect for one another.

I had a point.

So, what’s left? The final two episodes. Will Mer and Der get married?  Will Izzie live? Will Owen and Cristina get together? What’s going to happen to Bailey? To George? To everyone?

There’s a point to that too. You watch and you’ll see.

Thank you. From the bottom of my heart. For all 100 times you’ve watched.  For all 100 more you watch in the future.

I’m grateful.

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.