|Don't be like this man.|
Writing is a solitary act, no doubt about it, but to have something to write about you can't be a hermit. Which is to say that you can be, but you run the huge risk of not writing anything that anybody else cares about -- how are you going to know what is interesting people these days if you don't engage with them?
But if you spend a lot of time engaging with people, you may find yourself in the difficult position of having a billion stories to write without a moment to actually get any of them down. Interacting all of the time takes away the necessary alone time needed to formulate plots/characters and then put them on parchment.
There have been some very successful hermits, but from my experience (and you may be able to find better examples), the hermits don't write very much and are reported to be very cranky. The one that jumps out at me is J.D. Salinger. Hardly as prolific as his contemporaries. And then there's Ted Kaczynski.
There is also the balance of your writing life against the rest of your life. There is a certain truth to the adage that "a writer is always writing" and, to the extent that our life experience informs our writing, that's true; but you can't actually be actively writing/plotting all of the time without missing out on the world around you. Can people do it without burning out? Sure. But during their month long stay at the cabin in the woods on the lake are they catching any fish -- or are they shushing anyone who comes out onto the deck to chat because it’s too distracting as they write?
If you write to pay the bills then you have to treat writing like any other job. If you write to define your life then your self-identity can't afford a break to smell the roses. But if you write to enrich your life, to satisfy a passion, then you most assuredly must take time to walk among the living and partake of the richness around you.