I have had this impression of Guendouzi for a while. I suspect in training he plays the clown far too much and thinks far too much of himself, Arteta is not the guy that is going to stand for it, and thank goodness for that!
I said yesterday in the match thread that I felt he could do with being humbled and hopefully he learns a lesson. He needs to realise Arteta isn't trying to punish him, ultimately he's trying to save him from blowing his talent.
Regardless, it's shape up or ship out, Matteo. The Colney crèche is no more.
On a wider note, Arteta is just killing it for me right now. I like just about everything he says and most of the moves he makes. Literally my only slight complaint is that he's a little Wenger-like with his substitutions, but I'll give him that for now as we have ended most games strongly. I'm very content with who's running Arsenal for the first time in years!