thermodynamics - How does a diffuser increase fluid pressure?

In diffusers the velocity of a flow slows and the pressure generally increases. Nozzles do the opposite. My question is, "What about the geometry of a diffuser causes the pressure to increase?" I understand the conservation equations that net that result and I understand why velocity changes to keep flow steady.

What I don't have is an intuitive understanding of why a slower flow pushes harder per unit area, or if the the expaning geometry somehow causes increased pressure.