Fire and Nice is an episode of the Unikitty! animated series.
Unikitty prepares for "Problem Fixy Day", where the denizens of the kingdom come to her for help with their problems. Master Frown arrives to cause problems and enjoy the misery of others, only to set off Angry Kitty. The outburst causes considerable damage, and a horrified Unikitty decides to get Dr. Fox to remove her angry side. The scientist creates a machine that isolates and extracts Unikitty's angry side, trapping it and allowing Unikitty to to go about her life without the anger as part of her. However, Dr. Fox determines that her anger remains linked to her and senses the things that would normally be aggravating to her.
The problems of the kingdom-exacerbated by Master Frown-bring sorrow to Unikitty and cause Angry Kitty to become angrier and angrier as time passes. Eventually her angry side escapes and begins visiting vengeance on those who have been getting on Angry Kitty's nerves, much to her horror. The group manages to lure Angry Kitty into a trap using Master Frown as bait, and Unikitty is able to calm her rage. Having realized that her anger is a part of her, Unikitty asks Dr. Fox to put the two of them back together-only to find out that Dr. Fox is unable to do so.