I don't downvote as a matter of principle, but, wow, did I come close on this comment.
If I feel I need to communicate something, then practically by definition I am being selfish, self-indulgent when I do so. The world isn't asking for my comments, it doesn't need them, I make them because I WANT to.
But sometimes, sometimes, something one of us writes or records because we need to, because we want to, sometimes that bit of self-indulgence strikes a chord with someone else, resonates with them.
We are many who have been influenced by the writings of a cave dweller, by songs, by books, by poems, by encountering someone else's self-indulgent expression of an emotion that was for us inchoate until we found the other's words.
And then we understand ourselves.
I praise the self-indulgence of every writer who has ever dared expose themselves with words. I sing the glory of it.