I can't think of any early gen games I picked up better never finished, unless we count never catching em all in Pokemon.
Newer gen
Devil May Cry - dreadful
Fallout 3 - logged in over 100 hours, but never finished main story because I had seen the ending so many times due to husband and brothers playing it before me I knew what happened.
FF13 - I finished main story, did not go back for sub quests because the massive heart breaking disappoint.
***Oh wait Tomb Raider for ps1 stupid blind jumping/damn camera angles from hell
Newer gen
Devil May Cry - dreadful
Fallout 3 - logged in over 100 hours, but never finished main story because I had seen the ending so many times due to husband and brothers playing it before me I knew what happened.
FF13 - I finished main story, did not go back for sub quests because the massive heart breaking disappoint.
***Oh wait Tomb Raider for ps1 stupid blind jumping/damn camera angles from hell