Why is Civ 5 so addictive?

The psychology of game addiction is summarised in this book chapter:

http://www.isfe.eu/sites/isfe.eu/files/vg_addiction_chapter_2005.pdf

It's not too technical. Page 361 has a list of important factors in "addiction".

I think on some level it's difficult enough to feel accomplished when you execute some strategy yet simple enough that you don't need a college degree to learn it.

Add to that the flavoring of history and War and you have a great game. Which I think why Civ can persist as a series endlessly without getting stale like nearly every other AAA game. Honestly for all the frustration users have with every new Civ. A BAD CIV is still a Pretty Good game.

I think points have to be added for random occurrences in every game and the idea of replayability is BAKED into the core of what the game is. Other game franchises didn't focus on replayability until the used game market became a threat and even then they tack on bells and whistles and pray you don't sell your game. CIV, even the base game, is by definition replayable from the outset.

My final theory is that Civ plays on the theory that absolute power corrupts absolutely. Almost any leader that was strategic enough to solidify absolute power over his people has become entranced by that power. Some use it for noble gains and most commit terrible things. But none can give up absolute power. And Civ gives you a massive amount of power bottled and packaged into a tiny inconsequential world

For me well I hate to lose, so I can play it on immortal and win most of the time, but if I need a bit more challenge I can hop up to deity so I can swear at it a bit (especially when losing a wonder by 1 turn). I also like the map variety and exploring as others have mentioned and being the first to find some remote island or overlooked goodie hut. However it's not a true addiction I sometimes leave off for a few weeks to play something else, but it is like an addiction in that I start craving a game of it after the hiatus and them I'm back on a Civ 5 jag that can last months.

Looking forward to beyond earth Civ 5 + my favorite scifi, I'll probably never be heard from again (I just hope they fix some of the obvious dumb AI moves that no AI or human should make unless they are addicted to something nasty).