A common cause of frustration usually occurs when we are not able to separate our ideals from reality. It is further amplified when we put our ideals onto others. And that pretty much never work. Sometimes, because of our previous engagements or knowledge that we have acquired, we naturally have the tendency to paint the things we see with that same combination of brush strokes.
Until we can be at peace that the realities of the world are less often far away from the positive pictures painted in texts, we will always come across this block called frustration. Yes, it is ugly. No one likes to hear the world that they were protected from when they were young is actually a very dark place masked by the bright shining faces we see in our lives. But that is the reality. Love them anyways. Acknowledge it and move to a better place from it.