I have one.
I prepared an audition piece. The setup of the audition was where everyone stands in a line outside the door where you play. Everyone auditioning can hear you play. I had done my best but knew I couldn't quite play the piece -- but what the heck, they purposely pick more difficult pieces to spread out the abilities of the performers.
The first whammy -- I was the last person in line. Just about everyone -- in my mind every single one -- pretty much nailed the piece. The first person played, and I was impressed. Second person plays -- same thing. Third person plays and comes out worried that they missing one note. Fourth person nails it... fifth... I'm standing there just hoping to make it through the piece. Sixth person... seventh.... on and on... This was not a good way to lead into the audition of course. On the other hand, being last, I probably didn't have anyone listening to me. Some of the listeners/auditioners outside the door would criticize the performers -- they are playing it too slow, they missed a crescendo, that's not they way so-and-so does it and they know the judge likes that performer, they chipped a note there, etc.
The second whammy -- I was new to the place and didn't know what to expect. I walk into the audition room and see three audition judges -- two of which are nationally/internationally known figures. I had only seen one on CD covers. That was a nice, surreal shock.
Third whammy -- Actually playing through the piece. Usually I can just shake off nerves and play as I have practiced. However, in that case, there was that deep type of nervousness that can come up. And then when I started to play I remember my body felt very different -- I couldn't "mesh" with the instrument. It felt like my body didn't know what I was doing, like my hands were the hands of a beginner despite years and years of practice. Fortunately, I only have a vague memory of struggling through the piece, already knowing what the outcome would be, already knowing I was doing my best, fighting the nerves, was going to make a bad impression, and still had to go through with it all despite that.
And it was raining outside too.

Those experiences definitely keep you humble. I can always look back and know that things can't get much worse than that which is a plus for the future. (but the next time might come close, you never know...)