Grey’s Anatomy is known for its drama and thrills, but for its milestone Season 10, there will be “lighter, funnier” moments — especially for Meredith Grey and Derek Shepherd.

During a chat with TVLine, boss Shonda Rhimes revealed that MerDer, who has suffered many times throughout the years, will “probably” be the happiest couple on the show. Granted, they were one of the only ones still together in the Season 9 finale, but we won’t question it.

In true Grey’s fashion, they won’t be celebrating good times in every episode, though. With the new baby, there will be a big adjustment period, so things may dip for a bit.

“With a new baby, [being] post-surgery and the sleep deprivation, I doubt it’s going to be all happiness,” Shonda added, noting that maybe they have it all, maybe they don’t —  it “depends on what your definition of ‘having it all’ is,” she said. “And that’s sort of one of the things we’ll be exploring this season, for both of them.”

When it comes to “having it all” for Meredith, though, that means being at the hospital full-time and having a bit of an “evolution,” Shonda told The Hollywood Reporter.

“Meredith isn't going to take a step back from her career. She is going to figure out what it means to either be expected to or have people assume that she's going to take a step back or have that choice in front of her. We're going to watch Meredith have her own evolution,” Shonda dished to THR. “I call this Meredith's ‘lean-in’ season. She's going to discover whether or not that's who she is. We're going to watch her have her own evolution, which is going to be interesting.”

When it comes to her relationship with her husband, Derek, they’ll have some choices to make, too. “It's going to be complex and complicated,” Shonda said of their arc this season. Wait, what happened to the happiness?

Are you excited or nervous for MerDer in Season 10? Sound off below.

For more Grey’s spoilers, click here.

Catch the Grey’s Anatomy Season 10 premiere on Thursday, September 26, 2013, at 10 p.m. ET/PT on ABC.

Sources: TVLine, The Hollywood Reporter