Here's a very funny clip about professionalism under pressure.

The saying "The show must go on" can be taken to the extreme if you take in mind how performers are being called on to be on stage no matter what, because of the tight schedule a production brings with it.

As Freddie Mercury said "Inside my heart is breaking, my make up might be flaking but my smile stays on."

*Examples of that mindset was when Ace Frehley got electrocuted on stage during the "Destroyer" tour, he got knocked out but quickly re emerged and finished the show.
*During the "Machina" tour James Iha of the Smashing Pumpkins played a couple of shows with a high fever.
*At the Madison Square garden performances of Iron maiden during the "Power slave" tour Bruce Dickinson came down with the flu and performed, albeit sitting on the drum riser most of the time and having shots of oxygen in between songs.

So having said that, professional performers SHOULD be able to perform even when they would normally be incapacitated. So to test out how far this can go, the members of the Japanese humor show "Gaki no Tsukai" decided to test out their own professionalism by performing the fairy tale of "Momotaro" (Peach Boy) after consuming a large dose of alcohol...

How professional can one be if one is completely crapfaced?