There's something called a "defeat premium".

Simply put if you call a big stack with 5 2 os - and he has AK - if the flop falls:

K 5 2 (rainbow).

A 'good' player will KNOW that another 'good' player will never play pp below 55 and will be prepared to give up his stack as only an idiot will play 5 2 because its not even a decent connector. The odds will be against you (holding 52) holding AA (because he has an ace and also you didn't eat a chocolate biscuit when you looked at your hand) so any all-in by you looks like your trying to bluff down with QQ or JJ. You need sufficient implied odds to do this then it's a legitimate play. He may call an all-in.

Its even worse if this happens:

K 4 3

and then an Ace falls on the turn. at this point you not only get his stack but also his house and wife..........

The defeat premuim is "oh my god only an idiot would play those cards I must go all in" ) effect..

The odds that you make 2 pair or set or str8 with 5 2 os by the turn are 16% ish - so you only need your opponent to have about 15x the pot in his stack to make this a viable play. Its even worth calling a pot sized bet 'protecting' high pair as long as the implied odds remain. Big stack No Limit is not about pot odds - its about implied odds...

On Party on the lower limits I will always get stacked by someone who played for the gutshot draw

In addition to this there are also very threatening flops..

If he has AK and AJT98 (three suited) falls by the river then you can 'play the flop' -- i.e buff it down.. If your opponent is WT then he will put down.. iiregardless of what you've got becuase just about any hand you may have called with is will defeat him.

This combination of stack possibilites and dangerous flops makes these plays substantial in NL...

easy really....

Alex made one of these plays in real - discussed on another thread

hmm.. should I have told them this Alex???