Britney Spears by John Shearer/ Britney Spears by John Shearer/

"Why Should I Be Sad," described as "one of the most personal songs" off Britney Spears' forthcoming album Blackout, is said to illustrate how betrayed she feels by ex-husband Kevin Federline, with lyrics such as "Vegas... only brought the playa out of you." "The song is definitely about... when they were married," a source tells People. "Britney entertains the idea that she stayed home taking care of the kids while Kevin was out partying. The track... will be very revealing."

Us, meanwhile, is reporting that Brit was overhead saying, "I hate my [custody case] judge" during a recent shopping spree. "He is so mean. Just an old fart.... He paid me no respect at all."

UPDATE: No truer words! Superior Court Commissioner Scott Gordon has ruled that Spears may no longer visit her two sons, not until she complies with a court order. Though the court did not specify what directive Spears dissed, TMZ reports that she did not provide the folks doing her mandatory drug testing with proper contact information. The next hearing in the matter is scheduled for Oct. 26.