How important is it that a game you buy has online play?

How important is it that a game you buy has online play?

I don't like the standard now that everything has to have a multiplayer mode. I understand why it came about, on the business side, but I feel that it is just a waste of resources on some titles that could have better been used on polishing or expanding the story and experience. I am going to pick up Wolfenstein: The New Order from what I've heard about it, and I'm glad they didn't tack on a MP mode that wouldn't have a lasting community against the behemoth of CoD, Titanfall, BF, etc.

I also don't like how achievements are tied to MP, unless it is a MP focused game, like Titanfall or The Elder Scrolls Online. Knowing that the service can be turned off, rendering achievements unobtainable, or even if the service remains up the community might not be there to earn the achievement legitimately even a few months into the products shelf-life. I would prefer to see multiplayer achievements segmented apart from single player achievements for games.

*the term "legitimately" used in this post is not intended to reference boosting as illegitimate, I merely mean through normal non-coordinated play.

How important is it that a site has things in place to curtail massive spamming of the forums?

I honestly prefer online games, especially if there is an online function to it and my friends also have it because those are always the most fun.