A person's body speaks more than we often think. We generally tend to take our body language for granted. But it speaks a lot for us. It can also help us convey more than we want. When you entered a friends Apartments for the first time, you might remember the guard stopping you and asking you to record your entry in the register, which you otherwise also never intend to fill properly. Atleast i never remember writing my name on any such register. My favourite names(or shall i say pseudonames) in such situations is SalmanKhan or Vivek Oberoi. Jokes apart, moving forward and after going over to your friends place again and again, the guard starts recognizing you and you don't need to make an entry. Suddenly the guard changes and you can see that you're not stopped from entering. Does the new guard know you? Then how did he let you enter without stopping you? The answer is that after you've become a regular visitor to your friends place, going there is nothing new and the ease shows in your body language and the guard feels that you belong to the same apartments. You don't realise what your body language conveys
Another such instance would be entering a crowded bus. Do you really think the conductor recognizes and identifies each and everyone who's bought a ticket. If no, then how does he find out who's yet to buy a ticket? The answer is that he judges bodylanguage. The body language in a bus changes with time. If you don't believe me, just observe others in a bus. Observing yourself however would be an even better option. Enter a crowded bus and stand with a tired look clinging on the bar over your head, as if you've been in the bus for more than an hour and if you're stop doesn't come soon, you'll collapse. (Not advisable to try this in a bus with few passengers or at the first few stops of the busroute). You'll be surprised to see that the conductor doesn't ask you for your ticket. He really thinks that you've been in the bus for a long duration and even if he suspects you of not having bought a ticket, he would have second thoughts of confronting a frustrated man. Try this if you don't believe me. Afterall, I'm talking from experience.