One whiny bouncer is mad at Napster founder Sean Parker because he feels he stiffed him on a tip. A source tells us that as Parker was leaving a party at Trousdale in LA last weekend, the billionaire Facebook co-founder tipped security guards to say thanks. But one bouncer claimed Parker left only a $5 bill in his hand, rather than the bigger bill he expected. A rep for Parker fired back, “Sean provided hundreds of dollars of tips throughout the evening, but apparently this poor fellow isn’t deserving of even a cent of Sean’s generosity.”