I have to confess something. For quite some time, through all my university years at least, I used to think that to justify my existence in the universe I had to do something with my life to benefit others. I should be useful - produce things or services that people could use to make their lives easier - to feel happy and to earn my life, in a sense. This was a fundamental idea in my world view, one that made me stand a job I hated for two years.
I began to resent the idea towards the end of my degree, but as a person who doesn't like giving up, I pushed through anyways, got my master's degree, and continued working in the field. But soon enough, I got tired of hitting my head against the wall, quit my job, and decided to do more of something I wanted to do, regardless of if it was useful for anyone or not.
What I find interesting in all this is that I had already read Ayn Rand for years. I had studied these pieces of literature that underline the importance of man's life as an end in itself, and accepted the view. When it came to anyone else but me, I fundamentally though people should do whatever they wanted with their lives - dig for worms in the ground, if they wanted to - and it was the right way to live, because they had chosen that way themselves. Yet I was pushing the usefulness mentality onto myself, without knowing why, while fully realizing that this wasn't the way to go according to my own principles.
Think about this. Are you doing something, be it your work or some other venture, just because you want to be useful, or liked, or respected, or popular, or status quo? And what about what you want? This is your life, and you're free to spend it however you like. You can do the things your parents are expecting you to do. You can do the things that make people like you. You can work in projects that people find useful.
But make sure you chose that way yourself.
Worst case scenario? You realize too late that you've spent your life doing something meaningless, something that other people, society, or worse, yourself, have been pressuring you into doing. You're life is an end in itself. Take responsibility of it.