I read something. Rather I like it or not, the writer part of my brain automatically wants to write about it. If I like the ideas, and I'm not ashamed to say I actually read that, I might translate that into fanfiction.
Both trilogies are seriously alike. A sixteen-year-old girl from an overlooked faction/district in a dystopian society gets put in a competition with a limited number of winners and high stakes. At the end of the book, she becomes a major part of the rebellion - which fills up the next two books. However, the undercurrents of these two books are extremely different.