But I'm confused why you think gratefulness and knowing how "gave them life" is key. If my work-provided insurance plan pays for medicine I need to survive, who should I be supplicating myself to to satisfy your moral demands for appropriate gratefulness? Do I have less value as a human being in your eyes because I accepted payment from a faceless remote corporation instead of by begging my social network to give me the money?
Health care is not naturally given. Someone have to do it. And just like I do not owe you to write code on a whim, the same way doctor is not obliged to slave himself to provide health care for you. (Or are we back to slave times, except this time based on professional occupation?)
When specific doctor provides, or someone donates/volunteers their time/money/etc - you naturally grateful for that, or at least should be, otherwise good luck with that.
If you do not believe me, try to set up giveaway of some product. You immediately find out what I am talking about.