Frustrating indeed. But for a young lad lacking confidence I don't think the best tactic is to rip into him when he makes a mistake. It's counter-productive. From personal experience I've found that the best way to get the best out of someone is to be patient. Point out their mistake and ask them what they are doing wrong. Let them identify it for themselves. If performances aren't good enough you pull them aside and let them know, then support them in getting it right. It is hard to deal with the pressure to be the player the team revolves around, particularly when the team as a whole has been extremely poor.
He isn't consistent. But he isn't Alan Ball. He is 21. May turn out to be a world beater, and certainly has the tools in his bag to get there.
Ultimately you can't teach commitment. But what we as fans can do is get behind him and allow him time to get his head straight. Young players make mistakes and we need to give him grace when he does make those mistakes.
Because when he plays without fear, he is unstoppable. Who tries a first time curler from the corner of the box, or runs 70meters with the ball to lash it into the top corner? Who is surrounded by four players and yet can put a perfect ball into the box for Rom as he did last game?
Glimpses yes, but glimpses of a top player.
Get his head up, play with confidence in himself. Then we'll see Ross Barkley as he can be.