Susan Boyle Gets 'Exhausted'... Again

Who knew that taking a mentally fragile 48-year-old woman on a singing tour would create problems?

Susan Boyle -- you may remember her as a singer, or someone who very, very recently almost had an entire mental breakdown -- pulled out of tonight's "Britain's Got Talent" tour performance in Manchester. Officials are saying that Boyle's absence is nothing more than a "one off rest day."

Boyle has already performed three times on tour. That means she's only worked to the point of insanity 25% of the time.