Flat Design: When Should Design Go Flat?

I’m a fan of both flat design and skeuomorphism (realistic design style). But recently I’ve noticed that flat design is popping up everywhere. This isn’t a bad thing, but it doesn’t sit right with me. More and more people and companies are moving away from realistic, skeuomorphic interfaces, and trading their in-depth button designs for simpler, edgier ones. This had me wondering: why go flatter? Flat design done right can make an amazing layout and even better user experience. But is this why web designers started to favor a flatter look?