The Fundamental Theorem indicates that when you play in a way that lets your opponents know what you have, you may be costing yourself substantially. If opponents know exactly what you have, they will never make a mistake except on very close mathematical decisions. The more your play gives away what you have, the less likely it is that your opponents will make a mistake.
Yet you want them to make mistakes. Creating mistakes is, in a sense, the whole objective of the game. Clearly you might not want to raise immediately with three aces rolled up because you don’t want your opponents to know what a strong hand you have. You want to win more money from them on later betting rounds. At the same time, never raising with a big hand could be a mistake too.
The first game is no-limit. You’ve made a small raise, four or five people have called, and now someone puts in a substantial rearise. You must rearise again even if your play gives away your hand completely. It is worth dropping all disguise because as the pot gets larger and larger, what’s in the pot right now counts more than potential bets on later rounds. With two aces you should put in all the bets you can.