Abstractions should also simplify. If an abstraction makes something unnecessarily complex, then using abstraction for the sake of abstraction isn't useful. I

Abstractions should also simplify. If an abstraction makes something unnecessarily complex, then using abstraction for the sake of abstraction isn't useful. In the spirit of YAGNI, you shouldn't try planning too far ahead with your abstractions. From my experience, sometimes your clever planning all falls into place, but most the time something significant shifts in client demands and your abstractions don't make much sense anymore and add nothing but a layer of complexity to deal with that didn't need to be there to begin with.