I'm not going to show up to my last doctor appointment, can it be said out loud to someone now?
Why don't you want to show up to your last doctor appointment? I am appalled, and can't believe it.
I'm feeling better and I don't want to hear anymore stupid opinions about my situation.
There is nothing wrong with avoiding the doctor if you feel healthy, but it would be proper to cancel rather than simply not showing up.  It would be a sign of respect if you called and told them, and they should honor your request without causing drama.
Probably they won't care, I'll try to not think about it.
Not showing up might gain you a fee to pay. Most places like that state that unless you cancel within a reasonable time then you need to pay a no show fee. They care in that way.