Nancy Allen (Carrie) Carrie

Allen played Chris Hargensen as entitlement rather than malice

Nancy Allen's Chris Hargensen is not a sadist who enjoys cruelty for its own sake -- she is someone who believes she is owed something and will destroy anyone who threatens that entitlement. When Miss Collins bans her from prom, Chris does not simply accept the punishment. She tries to organize a revolt, fails, and channels her fury into a revenge plot that requires killing a pig, rigging a bucket of blood above a stage, and fixing a prom vote. The methodical quality of the plan is what makes Chris dangerous: this is not impulsive cruelty but cruelty as project management. (wikipedia)

Allen came through the De Palma-Lucas joint auditions

Allen was part of the same open casting process that produced the entire young ensemble. De Palma had originally steered Sissy Spacek toward the Chris role before Spacek's screen test redirected her to the lead. Allen took the part and made it her own -- playing Chris's cruelty with enough conviction that the character never tips into camp. (indiewire)

The seduction of Billy Nolan is Chris's most revealing scene

Chris's line "Oh, Billy, I hate Carrie White" -- whispered to Billy Nolan after seducing him in his car -- is both declaration and instruction. Allen plays it as someone who understands that Billy is already dangerous and knows exactly how to point him. The scene establishes the power dynamic that drives the revenge plot: Chris provides the intelligence and Billy provides the muscle. She promises him the rope pull ("And I'll let you pull the rope when the time comes") as reward, not collaboration.

Carrie launched Allen's long collaboration with De Palma

Allen married De Palma in 1979 and starred in his next two films: Dressed to Kill (1980), where she played a prostitute who witnesses a murder, and Blow Out (1981), where she played Sally Bedina, the film's emotional center. See Nancy Allen for the Blow Out performance. The three films trace an arc from villain (Chris Hargensen) to victim (Liz Blake in Dressed to Kill) to the complex figure between those poles (Sally in Blow Out). Allen and De Palma divorced in 1983. (wikipedia)