I've gone a bit further than that. You simply are. What you do is what you are choosing to do. In some ways, it is easy to see how you can be "defined" by what you do. But that is easily a distraction in many cases. Consider, few of us consider ourselves defined by how much we sleep.
In large, we are defined by what we define ourselves by. Sure, there are extreme cases where the world defines someone or something. But by and large, those are the exceptions.
I don't think we disagree that much. I'm more saying that there is no external definition of what we are. Most people are unknown to history. You can get bummed out about that, and it is intimidating.
However, it also means you are not necessarily held to any external definition.
I think this view has serious limits. In large, being in complete control of yourself is a luxury most people don't have. To that end, the views that folks can somewhat legitimately hold of themselves are greatly limited by their circumstances.
To play with both of our views together, the interpretations that you can honestly hold are going to be the responses of the stimuli you are subjected to.
Which is my way of saying to try not to get hung up if you are disappointed with any of the current state. It is, in many ways, fleeting. Keep what you can of what you like. Similarly, though, the fleeting nature of things is also irrelevant. If you liked something, continue to have liked that thing. No reason to change, unless you want to.
This sounds slightly contradictory to my earlier point. However, the things I collected now hold no value. That I collected them, though, I can fondly remember. If that makes sense.
In large, we are defined by what we define ourselves by. Sure, there are extreme cases where the world defines someone or something. But by and large, those are the exceptions.