You just do what you have to do. You can always get your nose in though. I've had my wife stand out in the street to stop traffic while I back out of the gas station when it's too tight.
It sounds crass, but sometimes you have to drive with the a calm and determined attitude until everyone realizes that nobody's getting in there until I get out. People don't usually pull into the gas station with their thinking caps on, but they get the hint when you sit there blocking everything with your raised eyebrow face like "well, are you going to back up or shall we sit here all day? I only have one way out of here though."