Frustration
/This points to a bigger difference, namely transcendent practices verses wuwei practices.  Can you really breath in unison while you are doing the dishes? Would you want to? But I'm not going into that right now. I just wanted to say this: If you are feeling frustrated during practice, it may simply be the way you are breathing. Yes, it could be that you don't like the person next to you, or that your teacher is trying to teach you too much, etc... But it is worth considering that it may be your breathing.
Frustration is a type of breathing.