What will surely go down as one the most stressful movies of the year is “If I Had Legs I’d Kick You,” which premiered Friday at the Sundance Film Festival.

Contrary to its title, everyone in If I Had Legs I’d Kick You has their appendages. Rose Byrne’s protagonist, however, does have a wealth of problems and neuroses, and writer/director Mary Bronstein dives into her headspace with a full-bore intensity and immediacy that’s bracing at first,

Rose Byrne plays a struggling mother, Conan O'Brien is her hostile therapist in A24's nightmarish "If I Had Legs I'd Kick You."