This really bugged me as someone who spent time working in retail.
Clinton was gracious, but I really felt like Justin Beiber calling him to apologize almost made the whole thing worse, and here's why...
1. Anyone who lived through his Presidency knows that Bill Clinton has a thick skin. As if he cared that a 19 year old pop singer insulted a picture of him...that is if he even knew about it before the apology! Considering that he work he does now is running a humanitarian foundation, I would assume he has better things to worry about. So it felt bit presumptuous of Beiber to assume Clinton was really that hurt.
2. Calling a former President of the United States personally to apologize asserts his own status and power.
3. There was no word on him apologizing to the restaurant staff even-though he wronged them much more than Clinton. He disrespected their property, and showed no regard for the fact that they'd have to clean up the mess he made.
4. Word has it Beiber used it as a networking opportunity, and mentioned to that he'd like to work with the Clinton Global Initiative. I guess apologizing to restaurant staff wouldn't further his career.