The faintly depressing human tendency to seek out and spend time with those most similar to us is known in social science as "homophily", and it shapes our views, and our lives, in ways we're barely aware of.
Even priding yourself on being open-minded is no defence if your natural, homophilic inclination is to hang out with other people like you, celebrating your love of diversity.
The unspoken assumption here is that you know what you like.
But if happiness research has taught us anything, it's that we're terrible at predicting what will bring us pleasure. Might we end up happier by exposing ourselves more often to serendipity, or even, specifically, to the people and things we don't think we'd like?