as a 15 year MMOG vet, let me just say:
they will eat your life up worse than crack.

i quit 'playing' them about five years ago and now i only play the ones i can sell gold on for real $, its the only way i can justify the timesink.

world of warcraft is designed to take up as much fcking time as possible. its trash.

seriously, as a former opiate addict who had a 50-80mg/day habit at one time i can tell you they (MMOs) are worse than drugs, especially if you have an addictive personality.
i was able to quit doing real, hard drugs easier than i could quit videogaming and actually did worse in school when i was on WoW than when i was a real junkie.

and my story really aint all that uncommon.

there really is no such thing as 'casually' playing a MMO, at least not for me

i sell gold on a lot of shards including my home shards Mannoroth (alliance) and Twisting Nether (horde) PM me if you WTB