State of mind where one becomes infatuated with another person simply because no one else is available. Out of desperation, one sees the other as the most attractive, most witty, etc, but fails to realize that it is simply by default.
Picture a classroom full of engineering nerds. There's 29 guys and one girl. Regardless of how mediocre that girl looks or how boring she is, all the guys will drool and fight for her attention. However, in a class full of hot girls, no one would even think about her.
All the guys have the island paradigm.