People are missing some nuance here.

1. Frustration depends entirely on the expectations of the outcome of an action. 2. Frustration is a spectrum. 3. Frustration is necessary to engage your full focus

If it were on a scale of 1-10. 4 through 8 would be the ideal frustration to keep you engaged in a goal. Below 4 and you would not be able to engage with the task fully. Above 8 and its a signal that either your expectations about the outcome are completely wrong or your approach is completely wrong, and you need to step back.

Playing your little brother in Street Fighter will never make you better at it, until he starts beating you and making you annoyed that you are losing, forcing you to concentrate and pay attention to the more subtle details of the game.

My definition of frustration: the gap between your expectations & perceived reality. The larger the gap, the greater the frustration.