It's rude to ignore someone on a business call.
Cameron is on a conference call with an important client when his favorite coworker, Dan, walks into his office with donuts.
Cameron wants to enjoy a donut.
Cameron quietly thanks Dan while grabbing a donut, then enjoys it silently as he continues his conversation with the client.
Cameron asks the client to hold, and spends the next twenty minutes joking around with Dan over donuts.
Cameron and his client reach a good deal, and Cameron is able to enjoy his donut.
Frustrated with waiting, Cameron's client hangs up and Cameron loses the account.