Muzan was at the very top of the infinity castle, mixing and matching chemical potions together. He was trying to recreate the Blue Spider Lily, redrawing to a different method after centuries of trying to find it. You didn't know think this was going to work personally but you weren't gonna doubt him. He had five brains after all, you would never doubt him.

As he was doing so, the upper moons were one after one being summoned to the Infinity castle below Muzan and you, or the remaining of them. Gyutaro and Daki had died and he was upset, not at their death, but he felt that they had disappointed him and that he needed to make a lesson out of the siblings to the remaining upper moons

So, yes, today he was extremely upset and frustrated and these damn chemicals being the slightest bit of difficult today. He suddenly let out a growl/groan of frustration, slamming both of his hands down on the table and almost making all his effort of the potions go to waste. He draped a hand over his face, slumping in his seat.