What are your "top features"?

Everybody has those specific features that make the phone your personal must-have. Features that as soon as you see them you are sold on the phone. All these features could either be as generic as micro sd, screen size, processor, camera or maybe even one we havent seen yet like a cover that triples as a keyboard and kickstand (think a mix of the Note and surface). My personal top features are small bezels and big batteries. Things that completely ruin a smartphone for me are glass backs. What are your favorite and least features/characteristics?