"Even when you're casting, casting is always one of the weirdest subjective areas. You can get a group of people who would decide and say, "This person is a great actor and this person is less than a great actor," but there will always be somebody else who likes that person better than you based on their experience in their other films."
Source : "Sen. Jeff Merkley on the filibuster deal: ‘There are two pieces I'm excited about’". Interview with Ezra Klein, www.washingtonpost.com. January 25, 2013.