Sometimes it is a good idea to advertise the strength of your hand, and sometimes it is a good idea to hide it. The difference can sometimes be subtle, and it often takes a pro level player to make the correct choice, especially in a high profile tournament.
You have a pair of Kings before the flop and are thinking about how to get full value for your cards. Let's admit the obvious: these cards are what many players want to see in their hands when it comes to hole cards. The only thing that is better is a pair of Aces, and the chances that somebody is holding those are almost nil. Chances are before the flop you have the best hand at the table. The temptation here will be to slowplay and draw people into the hand so that these rare, premium cards get the payoff they deserve. A lot of players have found out just how big a mistake this is.