Like me, I expect you know people whose idea of a conversation seems to be that you should mainly listen while they mainly talk, and the only time they encourage you to say something is if you're asking them a question - allowing them to talk even more. Although I was brought up to be a listener rather than a 'teller', as I get older I'm realising that there's often a sweet spot between these two positions. It's not always selfish to talk about yourself, particularly in moderation. A little self-disclosure can help people understand you better, but it's when both of you do so, when the confidences are reciprocated, that a conversation takes on a life of its own, allowing the two of you to walk away having had a good experience, sometimes even a great experience. It's not always easy to do this, particularly if your disclosure might relate, say, to the fact that you're not always a happy bunny.
Perhaps it makes sense to tread carefully, and to think before you disclose; only doing so if you believe it won't make the other person uncomfortable. An uncomfortable conversational partner rarely makes for a good exchange, but there's little that beats the pleasure of a genuine two-way flow of honesty.