title: OOP concepts confusion?
body: <p>While reading some programming books, I notice that the authors says that, in OOP, you may have some confusion while understanding the main idea of OOP.</p>
  
  <p>And hell yeah!. I had some confusion. Did you have the same and what makes this confusion to programmers(even experienced programmers)?!</p>
  
  <p>And if you had it, how could you beat this ?!</p>
  
  <p>Thanks</p>