Well, the fact is that if you're only in town for one day, it's not always easy to forge connections (or at least any substantial connections) and develop a social life. Perhaps you might want to rethink your daily routine and tweak it just a little to allow more time to meet people. If you're arriving at your daily destination with just enough time to have a look around the town and take care of shopping and accommodation, it's going to be nearly impossible to find the time for a conversation. Also, where are you staying? If you're one of these tourers who relies on "Stealth camping" and eating lentils and dried fruit from a supermarket... well, that's going to further reduce your opportunity to meet people. Perhaps throw in a night or two in a backpacker hostel if socialising is more important to you. Also be aware that sometimes you won't have a lot of control over the kinds of interactions you'll get, or the types of people you meet. I remember one guy in particular in Tasmania some years ago who was a little too insistent that I eat breakfast with him by the foreshore. I might have actually gone along with it if he hadn't been so insistent that he didn't even want to give me time to actually buy something to eat first.
Finally, the other thing to consider is the place you're touring. People in some places are just less sociable or approachable than people in other places. Some people are just more superficial because of the demands of the culture they live in. I've had more intimate conversations with people I've known for two hours in Europe than people I've known for 10 years here in Australia (no, that's not an exaggeration). That's simply because, at least in my experience, Europeans tend to be more honest, which makes me feel more comfortable in being honest. Finally, as others have said above, don't be afraid to initiate conversation if it's important to you. Most people will make it clear to you in one way or another if they want to be left alone, and when they do, it's time to move on and talk to someone else.
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I am clinically insane. I am proud of it.
That is all.