[Frustration is a part of it, sure, but the main reason Mikazuki hit it was that he simply liked to hit things and have the things hit him back.

He smiles fondly when Bolin mentions last year. Ah, sweet nostalgia.]

Oh yeah, last year was such a mess, it was great. Those Equalists knew how to show people a good time.

[Yes, Mikazuki honestly thinks it was fun.]

And like you said, it's best not worry now, either. At least we won't get bored!