I suppose we might (if one wants to get serious) oppose a habit of buying too many books by reflecting on this:
Is it possible that, in modern liberal* society, we get our day-by-day sense of who we are far too much by
--what we follow as fans (e.g. who we follow on social media, the sports teams we love, the brands to which we feel attached, the popular musicians and movie directors we keep up with, etc.);
--what we buy;
--who and what we oppose?
If you're under 40, you might add to that list, the places you've been.
If we stop to think about it, sure, we know there's more to ourselves than these things. I'm wondering if, though, in ordinary daily life, they don't account for a great deal of our sense of ourselves. If that's not satisfactory, then perhaps efforts to disengage ourselves from some of them would be advantageous.
*By which I refer to the modern western European and North American political, legal, and cultural norms