Set self aside?

Oh aye, this one rings many bells for me.

I rarely sing ballads, although I have done so in competitions. In fact, EKanne, you once judged me, and told me that I'd seemed to lose interest in the song halfway through, which came across in my singing. I suspect that was at the point where my mind started going "Oi! You! You can't do this. What do you think you're doing? This song's too long. Look, they're not listening. The judges are bored. And that was a really really bum note you just sang. What's the next line? What's the next line?!" This happens to me all the time, ballad or no, competition or no, and I am wondering if dealing with that sort of thing is what you mean by setting self aside.

Is it a novice thing? A confidence thing? Can it be dealt with by practice or experience?