I've been trying to quit for years. I'll likely get mocked, but it is quite addictive once you're hooked (particularly as it makes you tired, which makes you want to drink more to feel "normal").
I'm trying to move to sweetened Iced Tea (40% less sugar) and eventually unsweetened Iced Tea/water. But getting used to less caffeine/sugar actually causes legitimate withdrawal, plus kicking a habit is always tricky.
It has been linked to cancer (stomach, throat, mouth, the whole digestive system), diabetes, heart disease, and beyond.