I had the same problem when I first started using the UI way back when. Even before Mazzle was released, I was using mods like ArcHUD because the HUDs I had seen in PVP videos always looked nice. Unfortunately I found out that until you get used to using a HUD, you often unintentionally fall back to what was previously comfortable for you.
With just adding stand alone HUD mods to my old pre-mazzle UI setup, I found that I wouldn't even use the HUD even though it was right in front of my face and kept looking at my old character portrait.
Once I started using Mazzle though I couldn't do that any longer since the old portraits were not only completely gone, but the standard health bars were moved to a different location. So I had the choice of either getting used to and dealing with the new position of the health bars, or simply forcing myself to use the HUD.
Without even really realizing it, I've gotten so comfortable with using the HUD, that sometimes I forget I even still have the old fashioned health bars in the lower left corner.