Ah, the brashness of youth. Yesterday 16-year-old Freddy Adu went on a tirade of sorts, complaining about the amount of playing time he’s recieved this year and even (gasp) contemplating playing elsewhere next year. “I got [MLS] player of the week, and the next week I’m sitting on the bench,” Adu told the Post. “I’m like, ‘What is going on here?’ It’s frustrating at times when you think you’ve earned a chance to play on…