I'm not really thanking Diet Coke persay. But I do thank it for being the alternative. As a child and a type I diabetic, I was never allowed to have the birthday cake and ice cream, being such a high exchange load it would send me into ZOMG sugar issues even with my insulin shots (kids, this was before pumps were everywhere and carb counting was developed). So I didn't. But every birthday party and holiday, there would always be a supply of them for me. The caffeine would get me a bit buzzed and I'd be able to keep up with the sugar addled kids in the rest of the room and I would feel normal for just a bit.
As I grew older, it got to wear after awhile. Diet Coke AGAIN? No cake, no candy, etc. So when I was a teenager, I rebelled. I tried my first Skittles. I tried my first Starburst. I started drinking iced tea, Diet Dr Pepper, Diet Mountain Dew, Diet Pepsi, and other diet beverages as the 1990s anti-sugar and anti-fat campaign came into popularity. And it was glorious. Course, I still had the insulin shots to deal with but by then I was better at correcting for that. I still didn't have great control, but I had a much more flexible life. And I stopped drinking Diet Coke for a good ten years.
After college I found that the machines at work would have Diet Coke. It was always the cheapest at the convenience store. Since I'm a pretty light drinker, I also found most bars would have Diet Coke which was better than tap water. So I came back to it. It was like meeting up with an old friend and finding they hadn't changed at all. But I had changed. I had to migrate my relationship with Diet Coke from being the "alternative" to being the "mainstay", much like the can design changed from its original style to an updated version. My relationship with this beverage had reached its mature stage, much like Diet Coke reached the mature point of the product life cycle.
I still don't "love" or really "like" Diet Coke all that much. I tend to drink the alternative versions of it - Diet Coke with Splenda, Diet Coke Plus, Cherry Coke Zero, Coke Zero, etc. But its always there when you need it, helping out whenever there's nothing diet to drink (or really bad water/tea). I still don't like to dose insulin in my pump for drinks. And because Coca Cola's been around forever and will probably be around forever, I can always reach for a trusty Diet Coke when I need one.
So here's to you: Diet Coke. Thanks for being there.