A person who’s boring to me is someone who can only talk about people (including himself or herself) or, heaven help us, their pets, and not ideas or the larger world. The person has no independent ideas, no creative imagination, no ability to transform experience or sensory input into thought. They can talk on and on, but it isn’t conversation.
I imagine that I could be boring to people who do want to talk about celebrities, babies, and pets. That’s fine with me.
Not that there’s anything wrong with celebrities, babies, and pets, but thought shouldn’t stop there.