To use Hubski as a metaphor for a moment, it's like the difference between following users and tags. You'd follow a tag because it's a topic you're interested in, but you follow a user because you like what they have to say. A tag will only give you stuff that you know you want, but a person might post something on a topic you didn't know about. Each of us has a particular sphere that we like to peruse, some of which intersects with yours. When you follow a tag, you're just filling out your own sphere. When you follow a user, you explore a lot more outside your own sphere. Then, of course, your own sphere gets bigger as you discover new things.

Non-Hubski-specific answer: when you have something in common with someone and become friends or acquaintances with them, let them expose you to new things. If you like their choice in music, and share favorite genres, you might ask them what books they like to read. If you've never read those books, try them out on their recommendation and see if you can expand your horizons.

(Re-reading your question, I think my comment answers it in a roundabout way... short answer is I allow others to push me in new directions by showing me things we don't have in common (or didn't think we had in common as I was unaware of the topic completely)).