What is the most addictive game that you have ever played?

[Phrancheyez]

Uh..theres not a single most addictive. Let's see...

MajorMUD
Earth:2025
Diablo 2
Warcraft 2 (the last GOOD warcraft=/)
Phantasy Star III (playing it again..can't stop!)
And I was on Halo 2 pretty hardcore for a while..