Messing around in games is one of the most enjoyable ways to waste time, as while it's always fun to follow a main story and blitz through a game's campaign, chances are you'll have far more fun doing nothing but fooling around and playing with certain mechanics or systems to see what weird things they'll let you do or get away with.
It's why "linear" has become such a negative buzzword in the gaming community, and it's why gaming campaigns like Call of Duty's hand-holding shooting galleries just aren't as fun as something that lets you do whatever your sick, twisted (yet imaginative) mind wants instead.
Whether it's scaling the mountains of San Andreas or it's strapping a character to a train track in Red Dead Redemption, games are just better when they have a sense of freedom.
But, let's face it, no game actually lets you do whatever you want. The developers, for the most part, know what you can and can't do inside their game, and they work tirelessly to make sure you don't accidentally end up breaking the experience.
As a result, if a game thinks you're being too much a dick within its walls it'll end up punishing you for it - often in a gloriously tongue-in-cheek way that will leave you feeling a bit guilty (or a bit stupid) for trying it in the first place. It's all part of the fun though, and finding these hidden repercussions is often more satisfying than doing whatever you were supposed to be anyway.