The only medication I have ever taken regularly are pills for cholesterol. Actually, my bad fat levels are great but I am low on the good fats, the mono- and poly-unsaturated fats I think. I don't think my Doctor was very impressed with me when she explained this all out to me, sat there waiting for my reply with her usual stern look and then I replied "Whoohoo! More Peanuts!!"

In any case, it took me forever to get into the routine of taking a daily pill. Not because I don't value their worth or I don't value the advice of my doctor, I am simply a horribly forgetful person. Plus, they are supposed to be taken before bed as the body produces the enzymes or something or other that I am low on while you sleep. Quiet often, I stay up too late and I barely make it to the bed, much less remember to take a pill. Now that I am in the routine, it's more second nature but it took me months to become good at it.

Short version, not everybody lacks comprehension. Some of us just suck at breaking routines.