Don't make Novak Djokovic angry. Because he probably wants you to do that.
Winding up the seven-time Wimbledon champion, as some Centre Court fans did by accident or design on Monday, seems to further fuel his insatiable desire for success.
The 37-year-old Serb accused fans of being disrespectful during his fourth-round win, claiming they used the bellowing of his opponent Holger Rune's surname as "an excuse to boo".
"If there were people in the crowd trying to antagonise him and wanted Rune to win - that's the worst thing you can do," former Wimbledon semi-finalist Tim Henman told BBC Sport.