A couple of weeks ago I made the decision to give up Diet Coke, when I learned that Aspartame, the sweetener therein, is linked (anecdotally) to elevated liver enzymes, which I have (or had at the time).
Quitting it hasn't been as hard as I expected, with the addictive properties I believed the drink to have. The only side effect I've noticed is that there is no longer any brightness in my life. I have nothing to look forward to, and to reward myself with.
Who needs happiness anyway?