Normally i'm happy seeing that not all of my ETFs are green (or red) at the same time.
Recent examples are VXF (VTI - VOO), QQQJ (Nasdaq Next 100). Seeing the reds it means to me that i'm pretty well diversified; just waiting for the weak cylinders to fire later with renewed strength.
Somehow the old Growth vs Value has become Large vs Small. This could be longer theme since technologies affects most of the market.
But QQQJ seems keeping to be undervalued (also in the context of value of its stocks inside), and has trouble to catchup. I have no such worry with VXF, it will come back.
QQQJ shine time will come? I just do hope so.