*sigh* why do people glitch in games?

[alvarado52]

So while i was doing some random net searches on Halo 3 and GoW, i come across this website (i believe it was gearsofwarforums.com) where its basically jus like the HiH website (high impact Halo). So as i read through the forums and people talking about how they 'cant wait to rip apart this game', it really got the thinking.
Why do people glitch in multiplayer games? Doing it in a single player campaign hurts nobody, but when you do it online, it truly kills the experience of playing online, and eventually kills off the online appeal of the game in general (Halo 2 imho).
Where does it pop up in someones head to cheat and think it makes the game all that much more fun to play? And of course the argument will go 'well if the game designers left it there, why not use it?'.
That arguement is total shit. We arent talking about some cheap ass weapon/combo that the designers put in, we are talking about an exploit that will give the player an unfair advantage. Just because you can, doesnt mean you should, and definitly doesnt make you a better player skill wise.

Just a rant here,
discuss.