As I may have mentioned before, I am an atheist. As such, I see life as a temporary thing. One of my main goals is to experience said life as thoroughly and as richly as possible, and to make it better for others to the best of my ability. As far as I'm concerned, we only get one shot at things. If you aren't happy, then you need to change things until you are. Being miserable is a waste of time.
Well, that was all rather trite and preachy, wasn't it? What am I getting at here? Basically, I have had to make some decisions lately for the sake of my happiness that were probably going to make someone else unhappy. It felt selfish and mean, and was difficult to do. I spent about a week making the decision and talking it over with people. Why? If happiness is my priority, why was it so hard to make what was clearly the right decision for me? Because I was making the other person's happiness my responsibility. This is an easy trap to fall in to, one to which I am especially vulnerable. (I get like a -10 on the search check. It's an obliviousness penalty.) Fortunately, experience has taught me to recognize the trap and get out of it quickly. I told the other person how I felt, and things changed. The other person may be unhappy for a while, but their reaction to my honest feelings is their own responsibility.
Unfortunately, some people actively set this trap for others. Ex-boyfriends threaten to commit suicide unless you take them back. Parents claim that you are ruining their marriage by being gay. Another person makes their happiness contingent on you doing what they want. These are extreme examples, but this is emotional blackmail and it happens all the time. Taking a stand when you are caught up in a situation like this can be a difficult and heart-wrenching thing. I would encourage everyone to take a good look at this equation and make sure you don't fall on either side of it. If you do, please do something about it.
I don't care what you believe...if you're not happy, what's the point? Do what you need to do to be happy. I'm not saying you should go out and quit your job or tell your nagging mom to go fuck herself, but don't let other people's happiness keep you from yours. Unless you're Jean Grey or Superman, you only live once.