Pop icon Britney Spears made her second appearance on the CBS comedy 'How I Met Your Mother' on Monday, and may be heading back for a third appearance next fall. Spears' return as Abby, a "nerdy receptionist," marks a "triumphant return" for the "troubled star," said Owen Williams on Showbiz Spy. But she just doesn't have the "comic chops" for a long-term engagement, said Alan Sepinwall on the ...