It's not unusual for a boyfriend to get a little jealous if he thinks another man is muscling in on his girl - but telling the President of the United States to back off take some guts.
But that's exactly what happened to Barack Obama when he met a young woman called Aia Cooper at a polling station in Chicago earlier this week.
As he cast his ballot in a voting booth next to Miss Cooper, her boyfriend Mike walked past and told the married father-of-two: "Don't touch my girlfriend".
Miss Cooper was mortified, apologising to the President and asking him to "please excuse" her green-eyed other half.
But lucky Obama saw the funny side, replying: "There's an example of a brother just embarrassing me for no reason."
He then went on to suggest how Miss Cooper might re-tell the incident to her friends, saying: "I can't believe Mike, he was such a fool. Fortunately the president about nice about it."
But Obama, now on a charm offensive, wasn't quite done.
He put his arm around Miss Cooper and gave her a peck on the cheek, saying: "Give me a kiss and give him something to talk about. Now he's really jealous."