What's the big deal about taking a pill?

There are two people very close to me who recently have been prescribed medication but are failing to take the pills. They do not disagree with the doctor about the necessity of the medications. They just appear to believe that taking the pill is a large inconvenience. I don’t think this is an uncommon phenomenon, either.

I can’t understand their mindsets. I think being ill is a lot more inconvenient than swallowing some water at the beginning of the day. Can you help me understand what’s going on?