Simple or complex-- it doesn't matter -- there's likely an app for that. Problem is, we usually need to run into a particular problem before we realize the need for a certain app, and even then there are no guarantees we'll remember to download it while connected to the house Wi-Fi. That's precisely why some of us keep an ever-growing arsenal of utility apps that are necessarily part of each and every future phone we get. And you? You probably cross off at least a few categories found in the slideshow gallery below, but it's probably a safe guess that you're missing at least a few. Take a look.