Never, Ever Smoke
I use to work in the respiratory ward of a hospital almost a decade ago. I was young and everything and occasionally took a puff of smoke from my friends when we were out drinking. Only a few times, to be honest. One of my terminal patients held my hand one day, she was out of breath and I was trying to just be there to calm her down and give some reassurance.
She told me to never, ever smoke. She regretted doing it when she was young, as now she is dying because of it. She hated it because of all the damage. She described it as drowning, and said that when you are being choked, that sensation that you are losing your breath is just absolutely terrifying and the worst. Her words stuck with me, and in her final days, we kept her as comfortable as we could as she struggled to breathe.
She passed not too long after. Never forgot her advice. Never took another puff.
Story credit: Reddit / foreverjae