The 34-year-old rapper got some boos when he told that to an audience at a music festival in Britain on Saturday.
He ranted in the middle of his set about being misunderstood and underappreciated.
"I walk through the hotel and I walk down the street, and people look at me like I'm (expletive) insane, like I'm Hitler," he said. "One day the light will shine through and one day people will understand everything I ever did."
The multiplatinum-seller is known for his outspokenness, most notably his diss toward Taylor Swift at the 2009 MTV Video Music Awards, where he grabbed the microphone from her as she accepted the award for best female video and said Beyonce should have won it.
In 2005 he said "George Bush doesn't care about black people" during a Hurricane Katrina telethon.
The Associated Press contributed to this report.