The joke is old but have a look on Snowdown Graves
http://imgur.com/HDw2cIp Graves can smoke a carrot but can't have a cigar
http://imgur.com/HDw2cIp Graves can smoke a carrot but can't have a cigar
The carrot is our reward and the cancer stick is punishment.
His splash art has him eating a candy cane like a cigar too.