Movies You Aught Not Watch is Nick Rogers’ weekly, alphabetical look back at the 52 worst films of 2000 to 2009.

Sean Penn gave the most professionally shameful, cruelly wrongheaded performance ever nominated for a Best Actor Oscar in 2001’s I Am Sam — a film that deserved the bullshit-calling buckshot fired its way by Tropic Thunder.

Penn plays Sam Dawson, a mentally handicapped man endeavoring with his lawyer, Rita (Michelle Pfeiffer), to prove he can raise a daughter, Lucy (Dakota Fanning), whose IQ already exceeds his.

It was to such an oversimplified, insensitive extent that it was like watching a man mimic the mocking voice that kids who don’t yet know better use on a playground.

Jessie Nelson and Kristine Johnson’s awful script lives down to Penn’s ugly ineptitude. Sam dresses in short pants, endlessly spouts catchphrases (“That’s a wonderful choice!,” “You’re my lawyer!”) and turns no fewer than six mugs to display product placement procured for Starbucks. Stopping short of a Sam-and-Rita romance is as restrained as this ridiculousness gets.

Nelson also directs as if running through a film glossary (slow-motion, freeze fames, unnecessary handheld jitteriness) and Richard Chew’s editing would make Michael Bay’s head spin, one sequence seemingly cutting to a new shot for every syllable Sam utters.

Most atrociously, Nelson and Johnson simultaneously seek laughter at Sam’s limitations and scorn for those who would persecute them. In that cold miscalculation, Sam crosses from cloying melodrama to active offensiveness.

Long before Sam runs a literal victory lap with Lucy in his arms, it’s clear that you will not like it anywhere.