For me, it is the advances in modern medicine. I am 82, but likely would have not made it past 53 had I been born a generation sooner. At 53 I was found to have 90% or more blockage in all of my major coronary arteries. Without the bypass surgery performed in 1996 I likely would have not made it through another year before dropping dead. Then at 62, and becoming virtually crippled with severely arthritic knees, I would have been in a wheelchair for my remaining years had I been born sooner. But a double knee replacement 20 years ago gave me a new lease on life, even though I am going in for another knee surgery next month because the prosthetic has worn out in one knee. And again, back in 2014 a CAT scan, something not even dreamed of when I was born in 1943, used to locate and size a kidney stone that was causing me enormous pain showed that there was a mass on my other kidney. That turned out to be cancer and while I had to lose a kidney it saved me from dying from cancer, something that almost certainly would have happened without that saving CAT scan.
I'm also not taking the internet for granted. As old friends have passed on I find myself pretty much isolated nowadays other than my interactions with family. I still have a few friends to meet for a lunch together maybe once every month or two, but the internet has given me a window to the world and a way to be part of communities such as this one on rugerforum. If my house were to catch on fire, as I would run out the door I would be grabbing this laptop along with wallet, keys, smartphone and my LC9s.
I'll add that it doesn't take long to get used to modern stuff and take it for granted. I was at Costco yesterday and suddenly thought that my "small" TV of 65 inches was pretty pathetic compared to what I was faced with at the entrance to the store. I found myself looking at some 85 and even 100 inch models, which would likely overwhelm my small living room, but just thinking about it shows me how I take the amazing thing that I already own for granted. The first TV for my family was a 10 inch RCA black and white TV back in 1949, which blew me away when my Dad turned it on. How quickly we take the modern world for granted.