Diablo 2 lacked a lot compared to games like NWN, Baldur's Gate, but that wasn't really its goal. Diablo 2 was built to be addictive, and it was/is. Just some people get addicted, some don't.
My friends and I always played Diablo 2 on LAN, battle.net D2 never appealed to us. We would all start at level 1, and quest till we had beaten hell. Once done, we would make new characters and rinse and repeat, collecting items along the way. I have about 10 storage characters filled with uniques and 5 characters filled with green items, all of it is legit and there are no duplicates. I kind of wish I had been running xfire the whole time so I could know how many days I had spent playing that game.. but at the same time I'm glad I don't know.
I do know that I have spent at least 60 hours playing minesweeper...