Building a mobile app is both time consuming and expensive. And like any business, it pays to understand how your target market behaves and what motivates them to use (or not use) your product. While things such as ux design, bugginess and user engagement come into play, there's some interesting information to be found around what types of apps people consider most easily discarded.
What's very important to take out of this research by Alligatortek is understanding where your app development project falls. If you're building a social network, your going to struggle to get people to use it, but once they do they will be less likely to delete it. Whereas fitness and health apps have an easier path to acquiring users, but people find them more discardible.