Change? Yes, your real position may be established by the button, but preflop betting often establishes a new "Relative Position" that actually shifts the advantage away from the button. Although it happens more often in Limit Hold'em than No Limit, in some situations proper adjustment in the No Limit game can be significantly more profitable, when the shift occurs.
Look at this example: Player 3 limps UTG. The action is folded to player 6 who raises. The button calls and the Big Blind calls. Player 3 can now call and close out the betting with high confidence that he will be in position after the flop. The button may have "real position," but after the flop when the action is checked to player 6 who makes the expected continuation bet, the button is under the gun and player 3 acts last. This animation might help you visualize the situation against a super-aggressive player.Since Hold'em players, first in, often enter the pot with a raise and subsequently follow up with a raise after the flop this shift of advantage occurs often and the Big Blind tends to assume the relative button. Of course, if there is a reraise, any possible shift becomes highly unpredictable.
How can we take advantage of this Relative position? Well, we can sometimes call a raise with cards that in many cases would be unplayable. We can trap unwary players for additional bets, with our good hands. It also gives us a non-traditional way to deal with a loose-aggressive player. Normal poker lore suggests that we should always set to the left of the maniac. From that position we can re-raise and isolate against a loose player, but it is often more profitable if you sit to the right of the maniac, check your strong hands to his bet/raise then re-raise and trap any unwary opponents between you. Not only have you picked up an extra bet, but usually they will be faced with two bets to protect their equity in the pot. When using this strategy you must restrict yourself to those hands that can call a raise. Patience and discipline are required but it can be quite profitable if you have the right stuff. So, the next time you select a seat relative to that loose-aggressive poker player, you might want to reconsider and take the more challenging road.