Ok, but that's a bit misleading. Naroditsky is a GM, so he's not "just developing pieces" he's choosing pawn structures and development schemes that will give him opportunities later.
And when he attacks, he's not randomly making threats. If he doesn't see how or why an attack will work, he'll just keep making calm moves, building up his position.
Strong players don't attack when they feel like it, they attack when the position allows it (or demands it).
I am rated 1498 and I have trouble attacking. I feel like in my games I develop my pieces, and then start to attack, but my opponent seems to always defend well and it seems impossible to breakthrough. In Daniel Naroditsky's speed run he develops his pieces and proceeds to destroy his opponent. What am I missing? How do I attack?