didn't know how to take Joan's reaction to Peggy at the end

Joan's position in the firm is very much wrapped up in her gender presentation - she's the Woman in charge of The Girls, and she deals with the non-secretaries as Men. Peggy throws a big fat wrench into that.

Peggy is not an experienced manager. But I don't see Joan has much of a point. Peggy gave Joey a chance to back down, fired him when he didn't. The others may consider her a bitch, they also now know there are lines they better not cross.

I would see Joan as more "right" if Joey hadn't been such a hardcore asshole with Peggy. Peggy did have to fire him because he was not respecting Peggy. He was being a complete idiot the whole time. Sure, Peggy might be thought of as a humorless bitch - but I agree with Theo, that was projection.

I appreciate the fact that Don told Peggy to handle her business. The problem is that Joan tried to handle hers and she wasn't getting it done anymore. Joan was the one who left work early and cried, not Peggy this time.

That's true. Joan's way doesn't even work as well as it used to anymore, and she's blaming Peggy for going another route.

They also hit two different breaking points. Joan lost it after the vending machine incident, when she realized that she doesn't really have any authority - Joey doesn't even pretend to care about her place in the office hierarchy. She's fine after the picture, and she's fine in the elevator. She's a little mad at Peggy for having some power and wielding it, so she's sharp with her, but I don't think she's faking her nonchalance at that point. She had her cry and she's over it, for now anyway. I don't think she was even telling Peggy she shouldn't have fired Joey, just that she shouldn't expect Joan to be grateful that she did. They aren't allies, their positions are too different.

I see what you are saying, though I didn't perceive that she was really fine after the picture. No one who says to a group of individuals that she doesn't like them and that she won't mourn them when they die isn't fine.

I think she decided to wait them out.

You're right, not fine. Resigned, maybe. that that was all she could do and she'd best convince herself it didn't matter.

I wonder if we will see Joan go through a version of the transformation that Peggy has gone through.

she might if she becomes a widow or has a husband who is seriously disabled/impaired.

She had that little glimpse of what she could do when she was reading scripts. it would be a little surprising if another opportunity opened up for her, but it would make me happy.

I think Joan is likely to become more and more anti-feminist. A strong thread in this show is the building of the America that supported Nixon.