In earlier years, we only had the option of playing single-player games (or at the very least couch co-op multiplayers). Since developers have discovered that we are social creatures (by nature), more and more resources have been poured into the online multiplayer experience. I personally spend most of gaming time online, but I have a distinct appreciation for the cinematic single player experience. I believe that there is a place for both. It saddens me that with recent news regarding the not yet released Call of Duty Black Ops 4, there will be no single player campaign mode, and that's a huge bummer for such a franchise.

So my answer to your question is simply both :). I don't have a hard preference on which is better. Sometimes one is in the mood to relax alone and game, other times you wanna talk and game with your friends online.