Imagine yourself downloading an app which after opening, shows a very similar Home screen (layout & functionality) as Instagram. More photo sharing? Not for me, ciao.
There you have it. Especially on mobile where the screen estate is so scarce, think about what you copy and with what you (have to) come up yourself. Don't go for the red ocean, create your own blue one and live happily ever after. Kidding aside. Be authentic, innovative and hence delight your customer.