In episode 1 of House of Cards, when Frank starts breaking the fourth wall and talks about Vice President Jim Mathews, he says that he did his duty in delivering the keystone state, and adds that
...now they’re about to put him out to pasture. But he looks happy enough, doesn't he?
Then he ends by saying
For some it’s simply the size of the chair
What does he mean by this last part?
Judging by the context of the dialogue, the "size of the chair" should mean the title or position somebody holds. The size refers to the fact that the higher-ranking the individual, the larger and more impressive the chair they sit in is.
Frank is saying that although Jim is being retired, he's still happy because he holds the title and the prestige. The scene illustrates a difference between Jim and Frank - Jim wants the recognition, while Frank is after power.
The quote is actually:
For some, it's simply the size of the chair.
Traditionally, the size of the chair has often been associated with the rank of a person - the bigger the chair, the more powerful the person.
Therefore, Frank is suggesting that Mathews is "happy enough" because he holds a powerful position.
Frank was emphasizing on the fact that some people don't care about the power and authority that comes with a position but just being in that position alone is enough to make them happy. Jim was the president and he was to be retired, he was happy being the president and didn't care about all the powers that came with it else he would have fought to remain there.
In the story of Goldilocks, there is the porridge, the chairs, and the beds. If you don't care which bed you're about to retire to, but only about the chair you're in while you're awake, you aren't looking at the bigger picture.
