Why did Eren laugh when Sasha died?

Many people wonder why did Eren laugh when Sasha died? He laughed because Sasha’s dying words about “meat” are somehow ironic, since, so to speak, meat was all she cared about.

That’s why Eren remembers how we are shown how she stole the meat, which she then decided to share with everyone.

She “lived” for the sake of meat (everything related to the reconquest of land and other things) and died thinking about the very thing that she thought about all the time.

Simply put, it was bittersweet, that’s all, which is why Eren reacted in such a way that, given the circumstances, it’s not surprising that his reaction was wrong. (Of course, we also can’t just ignore Eren’s mental state, but that’s about all it takes in my opinion.)