Personal environment means the group of you and your closest friends – aslo called inner circle. Modelling your inner circle (or letting go of certain friends) can be a rather controversial topic. Many people will describe it as cruel, bad or just unacceptable. Others would say that you are only taking advantage of your friends. But I believe that say you are a product of your closes friends.
Your inner circle can keep you at your current level forever or it can propel you in space. After all, your closest friends listen to your ideas and share their ideas with you. You reach out to them for advise and they reach out to you with the requests. You recommend books to your inner circle and you read the books they recommend. If you are lucky enough you might also be brave enough to start a company together, or they can recommend you to join their companies.