Much poker tournament strategy revolves around understanding the significance of stack sizes. Smart players are always aware of the amount of chips they (and their opponents) have relative to the blinds and antes, as well as how stacks compare to each other.
Accumulating a lot of chips and becoming one of the leaders is always nice, but some players are more comfortable than others wielding a big stack, particularly if their "normal" doesn't involve being aggressive or applying frequent pressure on opponents.
Team PokerStars Pro Daniel Negreanu returned to his YouTube channel recently to offer some concrete advice to tournament players about how to play a big stack.