In most societies, it's perfectly acceptable to be inquisitive, especially when it comes to matters of public interest. However, most of the time, it's best to keep to yourself and mind your own business. If you're in the workplace, at a public place or at a social gathering, it's not polite to interrupt other people's conversations and just butt in with your own thoughts and opinions.
It's human nature to be inquisitive, and you might want to satisfy your curiosity, but social norms often dictate otherwise. Here are a few ways you can keep yourself from being nosy.
Keep your focus. If you're at a public place, and you overhear an interesting conversation, try to steer your mind away from it by keeping your focus. For instance, you might be at a restaurant. Keep focusing on your meal. If you're in public transport, read a book. Do anything that will keep your mind off of other people's business.
Focus on your work. At the workplace, gossip is common, especially when there is idle time. Try not to pry into your work mates' personal lives, as this might only cause trouble. Instead, focus on your work. When someone approaches you wanting to make small talk or gossip, ask instead about work-related matters. Tell people you're a bit busy, and that you can talk during the break or after office hours.
Maintain your own space. When you're out in public, you can keep yourself in your own "bubble" by defining your space. Most people do this by using portable media players like an iPod or Zune. When people see you wearing earphones, they will steer clear from you, thinking you don't want to be disturbed. Similarly, when you listen to music on your earphone, you drown out the conversations from other people, therefore effectively keeping to your own.
Don't tell too much about yourself. One way of effectively minding your own business is by not being too open about yourself. If you tell your coworkers too much personal details about your own life, they will take it to mean that you also welcome details about their lives or that of other people. By keeping a safe distance, you will give the signal that you're not too interested in gossip.
Be polite. When someone offers to share juicy gossip, or try to ask you questions that are becoming too personal, politely decline, saying you're not really into putting your nose into other people's lives, and that you would rather keep to your own business, yourself. Minding your own business is not a crime, and it's a sign that you're a mature, respectable individual.
As with anything, the essential thing to remember is balance. When you're with your coworkers, there is a healthy limit to how much you can be personally involved with them. When with friends, you can talk about your own lives or other people's lives without being too intrusive. Learn to empathize without necessarily being imposing. That's how you mind your own business.