Turns out you can’t just go around telling line judges, “I swear to God I’ll fucking take this ball and shove it down your fucking throat! Do you hear me? I swear to God. You better be glad–you better be fucking glad that I’m not, I swear,” during a semifinals game at the US Open. I mean, you could, but you might be fined and lose the match like Serena Williams did.

Williams battled Kim Clijsters during a semifinal match on Sunday when she blew up after being called for a foot fault which resulted in a double fault. A point penalty was given for the outburst which gave Kim the win. Serena was also fined $10,000 and an investigation has been opened to look into her “threatening manner.” In addition, another $500 was taken away for Serena smashing her racket after the first set of the match.

People just don’t understand. Sometimes you get emotional during a tennis match. Like last week when I was losing to this 13-year-old, I got so mad I smashed the racket over my knee. Apparently rolling on the floor clutching your knee and crying isn’t as intimidating as you think.