I would like to know why. I was never a big fan of Fallout games: I played Fallout 3 but never finished it. I finished New Vegas but never replayed it. Yet, I'm absolutely loving Fallout 4: 1000 hours in, at least 5 different complete playthrough, a dozen partial playthough, extensive use of mods, creation of character builds, I'm totally invested. I must say, I'm not a hardcore gamer normally: I don't have a "list of games", I play one game and I stick with it until I find a new one.
The only other game I put 1000 hours into was Civilization V. It took me YEARS to get to 1000 but I reached that number in a matter of months in Fallout 4. I must admit I'm a big fan of Bethesda games. I have played Skyrim a lot but never to the extent I'm playing Fallout 4. When there's gameplay involved and character creation and development, I'm all in!
Fallout 4 might be the best game I played since Diablo back in 1997!