Your mother was right. If you don't brush your teeth, you'll get cavities, and too much television will turn your brain into mush. But there is one piece of advice that you're better off disregarding because you absolutely should talk to strangers.
Your future success is predicated on relationships you have not yet made. And if you are interested in finding better referral sources or upgrading the quality of your clientele, you will need to start infusing new people into your network. The best way to do that is to boldly initiate conversations with unlikely people.
Whenever I travel for business, I make sure that I'm placing myself in surroundings that are conducive to meeting strangers. I'll get to know the person sitting next to me on the airplane. I'll sit at the sushi bar and the cocktail bar in the hotel lobby so I can strike up a conversation with the people around me. When it comes to traveling, my business development strategy can be summed up in two words: avoid tables. As a result, I frequently find myself in dialogue with people from industries that are vastly different from mine, with circumstances that I would not be likely to find within my usual network. These random encounters have led to quality time with executives and world travelers whom I wouldn't have otherwise met.
So, avoid tables, talk to strangers, and listen to your mother about everything else.