13. John Ratzenberger
Ratzenberger was once best known for playing Boston-accented know-it-all Cliff Clavin on "Cheers." Over the past 20 years, however, he's enjoyed a second career as a voice actor. Pixar considers him such a good-luck charm that he's had a supporting role in every single one of the CGI studio's features, from 1995's "Toy Story" (he was Hamm, the piggy bank) to Fritz in the new "Inside Out." His truck in "Cars," Mack, got a nice in-joke during the closing credits, when, while watching car-themed versions of past Pixar movies, he realized that the supporting characters he liked were all played by the same actor -- namely, Ratzenberger himself.