I've mostly quit drinking. I used to drink and smoke when I went out on the weekends. It made me feel like shit later no matter how much I loved it. I've cut down on the caffeine (switched to decaf and decaf tea) and it's helped a lot, too. I didn't realize how much I was taking in until I stopped and thought about it.
2 cups in the morning, a couple cokes during lunch, a cup of coffee in the afternoon, and maybe a cup of tea or a couple of glasses of tea after work.
"How dreadful!" cried Lord Henry. "I can stand brute force, but brute reason is quite unbearable. There is something unfair about its use. It is hitting below the intellect." ~ Oscar Wilde - The picture of Dorian Gray