This goes all the way back to Aladdin, but Robin Williams was extremely unhappy with the final outcome of the movie. My understanding all voice talent in the films are paid union scale for voice work, whatever that is.
The movie, of course, was a huge hit, almost entirely due to Mr. Williams' shall we say unique and frenetic humor (Tangentially, how in the world did he live through the late 70's and early 80's? Trivia question, who was the 2nd to last person to see John Belushi alive? Robin Williams.)
Robin felt he'd been exploited by Disney, and he expressed this feeling frequently and loudly. Disney's solution? They sent him a Picasso as a small token of their gratitude.
You know, I really bleed for my employer. A raise of bonus would be okay, but a Picasso would be a more appropriate gesture, don't you think?