We all love a letter

Dear Sir, thankyou for the opportunity to waste my time confirming that Kylie is fit to appear in a televised school play. Stephen Hawking, Terry Pratchett, Stevie Wonder, umpteen children with cancer and endless smashed up A+E patients on TV, all seem to manage this without undue incident. Could you possibly, for my own education, furnish me with a list of any conditions, other than death or fulminating infectious disease (either of which, make their attendance unlikely) that would render Kylie, or any other human being, incapable of getting on with this onerous task.....P.S. Stage fright doesn't count.