Are you a firm believer that people come into your life for a reason?

It's completely random who happens to cross my path and they not as much come into my life as I pick who I want to give my attention to, probably based on my already existing prejudice that I carry with me from my family and previous experiences with people. Of course, certain types of people don't even have a chance to come into my life as I avoid places where I'd be more likely to meet them. I believe that from a large part we are responsible for the kind of people we surround ourselves with. The rest of encounters are completely random.