What is meant by the adjective East Coast? You are so East Coast?

That usually means New York- urban, sophisticated, many a little driven. Not laid back and beachy. I would take it as a compliment.

Possibly Liberal but not a West Coast liberal type of liberalism. A greater good liberal rather than a "do what you like" liberal (Roosevelt liberal rather than hippie liberal). The regions of the US do have a typical character, really a caricature or stereotype, that derives from its history.

Could also be more work ethic oriented than pleasure-driven oriented. (more business than artsy). Context would matter somewhat.

In the USA, it normally is related to the urban centers along the east coast from Washington to Boston and the cultures there. The south would not be part of it, except maybe Miami.

The person who says you are so East Coast is probably saying you are uptight.

It is used in the USA as a sociological description. Not used thus in Britain, where "East Coast" is almost purely used geographically.

It means one who has the characteristics of someone from the eastern seaboard in the US as opposed to a mid-westerner or a west coaster.

intense and political?