The Charm of "Bad" Design
Pretty pixels used to be a signal of an app's quality. Not only is that no longer the case, but there might even be merit to being ugly by design.
Yet I don't think we should take it for granted that a pretty user interface is always good for apps. I'm positing that there might even be a class of apps for which it would have been detrimental.
Snapchat and Reddit might offend my design-snob sensibilities, but their only a developer could have made something this ugly designs convey an earnest charm that's absent from so many social networking apps. Snapchat in particular looks like something made by kids for other kids, which I believe makes it seem relatively innocuous and therefore safe to post the kinds of risqué photos it's known for. Would you rather pass your nude selfie through the servers managed by a bunch of seemingly harmless kids, or the servers owned by a publicly traded company (Facebook Poke)?

Compare that to, say, Google+ and Facebook, which have been polished into sterility. Or even iOS 7 , which, in spite of the splashes of neon, can sometimes feel spare and cold. Weeks after my wife, a very light user of apps, switched from a Nexus One running Android 2.0 to an iPhone 4S running iOS 7, she complained that her Nexus One was more "comfortable". You get a sense that some things in iOS 7, like the absence of button borders and now the shift key, were overthought.
Some felt that iOS 7 lost its sense of whimsy and playfulness. That's why iOS 7.1 includes a guessing game built right in to the keyboard
— Horse iOS (@Horse_iOS) March 13, 2014
The average user's aversion to "overthinking" is what can make pretty designs difficult to trust, and rough, developer-graphic designs occasionally more inviting: If a software team doesn't appear to have put too much thought into design, you might also assume that they haven't put much thought into the more insidious, calculating aspects of software we've grown to distrust.
¯\_(ツ)_/¯