I think how much you immerse yourself in the game, the people you meet and the roads you take greatly influence how much of a draw FFXI can be if you do decide to quit. A lot of the people I have know to quit have come back occasionally and dabbled but mostly stay away, but they also never really got as involved as myself and some of the friends that I have now made.
Of course, there are many many varied reasons to leave, from being served divorce papers, to a change in circumstance that makes your departure involuntary.
One such was Elfaria, who had a drastic change of circumstance resulting him taking a break from FFXI. Sadly this seems to have been a greatly extended leave of absence. There are people who I really do wish were still around, one such being Elfaria.
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Crazy, French and Taru! He was just a lot of fun to be around, with his sly remarks which were always spot on, his determination and dedication to his jobs, insane magic bursts or busting out the WS on his SAM he was intense and hilarious and I miss him ooodles >.<
So a toast to those who have gone on and yet still remain in our memories. Wish you were still here. I think a nice red would be appropriate about now LOL and some fine cheese.