She probably didn't get Miss Congeniality either.
Characters often take defeat really poorly, even when there isn't that much of a consequence for losing, and especially when they lose fair and square.
This can be any kind of competition, from a friendly game of cards, to a national spelling bee, to an argument about who does the dishes that night.
And how the character takes it can vary. They can fume and pout for a few minutes, to spending most of the episode trying to get revenge.
Sometimes the loser can be vindicated if it turned out there was cheating, but that's uncommon. Or it might turn out that the winner wasn't properly announced, and the character actually won, but jumped the gun in complaining.
A Sister Trope
to Second Place Is for Losers
(and usually overlaps unless it's not the loser that thinks this), Unsportsmanlike Gloating
(being just as sore in victory).
Contrast Graceful Loser
No Real Life Examples, Please!
: We don't need to call out people for bad sportsmanship.
- In Muppet Babies, Miss Piggy loses a race, and then insists they need to go another lap.
- In this issue◊ of Betty and Veronica, Veronica double subverts this by wanting to show what a good loser she is in the Beauty Contest, but then shoves the trophy in Betty's face.
- In Beverly Hills Teens, Bianca holds a costume contest for Halloween, and after a couple Dresses the Same situations with Larke, Bianca still loses, and then throws everyone out of her mansion.
- After Franks wins the first race in Hidalgo, an upper class gentleman he raced against whined is a subtler way, by claiming Frank's horse shouldn't be a race horse because he wasn't a thoroughbred (which turned out not to be a good idea with Frank).