Another night of frustration was too much for Chelsea's volcanic striker, whose petulance rose to the surface again like a teenager's acne during the 2-2 draw at Stamford Bridge.
He tried to get Claudio Yacob sent off for a second bookable offence early in the second half – he may have had a point, but it wasn't Costa's call to make.
On the final whistle, he marched towards referee Anthony Taylor like an angry fishwife administering the rolling pin to a wayward husband.
Then he tried to pick an argument with West Brom keeper Boaz Myhill before stomping down the tunnel, punching the perspex wing like a child ordered to finish his greens.
What a performance. One of Cinderella's ugly sisters couldn't have done it any better when the glass slipper didn't fit her foot.
And when Costa's squealing had subsided, Chelsea lost more ground in their pursuit of a distant top-four finish.
Manager Guus Hiddink, asked if Costa had strayed close to the frontier of acceptable limits, made a small gap with his thumb and index finger, chortling: 'I think there was a little space left.
“The central defenders were provoking him and he was causing danger continuously. It (the aggression) was mutual.”
And that dent in the tunnel? “We can repair that easily enough, that's not a problem,” shrugged Hiddink. “He is an emotional guy and I like that very much.
“If you have to push your players (to get angry) it's difficult to survive in the Premier League.”
West Brom, who twice hauled themselves level, we can deal with summarily. It wasn't always pretty, but they deserved their point.