Long before I came a PT, I knew that above and beyond anything I would teach my clients, balance would be the most important thing. Balance isn't something you find, it's something you create, and a balanced life is the greatest gift you can give yourself.
Life is sadly sometimes full of extremes - we work too hard, we sleep too little, we drink too much, we party a lot. Doing too much of one thing, whatever it may be, puts an enormous amount of pressure on so many other aspects of life. If we work too much our relationships can suffer and our stress levels can become unmanageable. Too much partying and late nights will have a detrimental effect on our health, as will too much exercise. You may find your happy medium at any part of that spectrum, but as along as you are happy, healthy and fulfilled it's not important which end you might be veering towards.
Completely cutting out things from your life, or including too much of them within, is far more likely to cause trouble later on. Of course there are some types of people who have the willpower to consistently stay focused, but isn't that perpetual denial of things you enjoy ultimately just as negative as succumbing to a weakness or desire? When we deny ourselves things; rest, food, TV, parties etc, we place ourselves in an automatic abstinence cycle which will no doubt culminate in craving them more at a later stage.
We use January to define a period in the year where we may abstain from certain things - drinking, raving, eating meat etc. But a balanced life need not conform to these types of short-lived 'health-kicks', although of course it's important to educate oneself on how much of any one thing may be too much or too little.
Think about what makes you smile. Is is chocolate? A glass of wine? Lifting weights? Dancing all night? All of the above? Do all of them. It isn't a weakness to do the things you love - totally the opposite! Staying healthy and happy doesn't mean just doing the things that are 'healthy', it's about enjoying yourself and enjoying life. And like I said, a life that you enjoy is a gift - so go ahead and give yourself the best present you'll ever receive.