It's all personal preference though. Myself, I don't find hack and slash particularly engaging; thusly I found both Diablo and Diablo II to be tedious. That said, they're certainly not bad games, simply... overrated or not to my tastes.
I personally took a great dislike to Dreamweb though, possibly one of the least rewarding games I've ever played. I' not sure if it would qualify as my worst game though, even Dreamweb had its moments.