TLDR; My sister would be dead if we were under universal healthcare.
Note: I base my views on America's attempts at UHC. Other countries may have done it 8292629181926272 times better and could completely overturn what I have to say, but this is my personal perspective.
My family has always been considered working class. We've never had a lot of money and both my parents had to constantly bust their asses working to make ends meet.
When I was around 7 years old, my little sister contracted a virus that caused her heart to swell and slowed her pulse down to the point her blood was barely circulating. She eventually went through a heart transplant surgery and made a full recovery. However, when she was 6, her body began rejecting her transplant and caused her immune system to attack her heart which lead to another transplant. Something went wrong in the procedure and caused a tremendous increase in blood pressure. This lead to her having near constant seizures and caused serious brain damage.
She's made a decent recovery since then (she's 13 now and probably the healthiest out of my entire family as far as eating habits and exercise go) but the only reason she's still here is because of the insurance my dad used to have.
The average cost of a heart transplant in 2011 was $997,700. My sister has had TWO of them. So $1,995,400 (not including the operations from her brain trauma) was our bill. The insurance we had back in 2005 (first transplant) and 2011 (second transplant) covered almost the entire cost of both transplants and the procedures after, allowing us to have paid off her first transplant comfortably before her second one.
Now, our healthcare bill is more than double what it used to be with less coverage and my sister's medicine is becoming increasingly expensive because we have to pay more out of pocket due to our Insurance covering less.
I've seen people in this thread talk about the feeling of being too poor to afford treatment and needing UHC, but our nations attempt at it would have made it unaffordable for us to begin with if it had happened 12 years ago and my sister would have passed away before she was 2.
Universal Health Care is a great idea and, if it's done correctly, could benefit everyone. However, America just can't seem to pick something and stick to it. If we somehow manage to get a system that works, I'm all for it, but what's already been done has left a sour taste in my mouth.