The best way to be an extremely boring person is to have only one interest and obsess over it non-stop. I once worked next to a guy who only ever talked about rock climbing; no matter what you tried to talk to him about he'd find a way to bring the conversation back to his rock climbing hobby. To a fellow climber he might have been at least slightly interesting, but to me he was so memorably dull that here I am, five years later, using him as an example of dullness.
If you put up a bust of Spock in your office, you're basically saying to the world "Hey world! You know that TV show which maybe you used to like a bit when you were a kid? I think that's one of the most interesting things in the world!" This is generally a pretty good indicator of a fairly narrow range of interests which will make you pretty boring to others.
Anyone who really thinks that a long-defunct TV show is interesting enough to make it a significant part of their identity really needs to start developing a few new interests.