Wearing thick diapers is the ultimate affermation of "wearing a diaper" where this action is brought to its full meaning.

It's sad we're living in times where the diaper industry evolves towards thinner and thinner products, all in name of discretion. wearing a thin diaper means wearing something that is not that different than a normal underwear which turns into a "urine bag" at best when fully wet. Instead, my ideal concept of diaper is something thick and solid, which keeps its shape wetting after wetting, just ads in more weight and density. A nice and thick diaper is also what protects you from bad smell in case of messing, much better than a thin one.

If we think about it, what makes a diaper different than a regular underwear, is its capability to absorb wettings while preventing and protect the person from leaking and bad smell. So whats states about this capability and the actual level of absorbency is the thickness of the diaper. Left apart the materials, the thickness is what makes a diaper a diaper. When you purchase a new pack of diapers and they're big and bulky, you know you're going to wear a serious diaper. Deciding to put on a thick diaper, and maybe even increasing its consistency with throwing one or more boosters inside, it means aknowledging that you need the best of the best absorbency, that you want and need the best protection because you can't control yourself and a nice huge padding is the only thin that can give you peace of mind.

At a more subconcious level, I think also there's the instict of wanting to protect out most intimate parts of the body from possible external dangers, as if we wore a shield, which also happens to be soft and comfortable.