Walt disney enlaces - How Inside Out director Pete Docter made Joy so joyful 

Pixar's 'Inside Out' clip: 'Who puts broccoli on pizza?'

Judging by a slew of rave reviews from critics and an impressive opening weekend at the box office – it’s now estimated to reach $92 million in ticket sales across nearly 4,000 theaters nationwide as of Saturday morning – 

appears to be the epitome of a perfectly crafted Pixar film. The feel-good feature tracks the story five quirky emotions that live inside the mind of an 11-year-old girl named Riley: Joy (Amy Poehler), Fear (Bill Hader), Anger (Lewis Black), Disgust (Mindy Kaling), and Sadness (Phyllis Smith). Though one might rightly expect that a film about the inner workings of a pre-pubescent girl’s brain would be somewhat complicated to make, designing the main character of Joy unexpectedly became the greatest challenge for director Pete Docter (

“There are many, many flavors of Joy,” Docter told

earlier this year. “Without a doubt, she was the most difficult character to create.”

It took nearly 18 months for Docter and his team of six designers to arrive at the final version of Joy, taking her from a giddy gamine sketched in black and white to a blue-haired sprite in a yellow smocked dress.

“Pete was always concerned with Joy not being annoying. There’s a certain point where if someone is overly happy all the time, they become really annoying,” character designer Albert Lonzano shared with

in an interview this March. That being the case, the

design team decided to explore “a lot of different avenues” of Joy’s personality, Lonzano explained. “A tomboy, being kind, mischievous, kind of a rascal-type …[and we wanted to] play around with Joy, like what does she look like when she’s sad?”

Ultimately, Docter considers Joy successful, and not because her pixie cut captures her sweet sensibility just so. “This character drives our lives,” remarked Docter.

“I think that’s why I was super excited about the concept from the beginning, because with animation, you can express feelings stronger than with real people.”

•Pixar’s Lava: Behind the scenes of a love story spanning millions of years

\'Jaws\' at 40: Steven Spielberg on how it was almost a different movie

Jake Gyllenhaal does the best Arnold Schwarzenegger impression

This was the most difficult part of making \'Inside Out\'

\'Jaws\' turns 40: What critics had to say about it in 1975

Laverne Cox explains powerful message behind her recent EW cover

\'Simpsons\' video squashes rumors of Homer-Marge split

10 novels about summer vacation to read on a getaway

\'Big Brother\' portraits: House guests introduce themselves

Ken Regan\'s \'60s celebrity photos: Classic looks at The Beatles, Frank Sinatra, and more

11 celebrity lookalikes: Ever get these pairs confused?

Susan Sarandon, Nick Cannon & Goofy, Emmy Rossum & More!