From NaNoWriMo communities and writing critique websites to local and university groups, there are many different ways for people in the world's loneliest profession/hobby to find like-minded people. Those who join writing communities are often seeking to improve their own writing, and they're more than willing to help you improve yours.
1. You aren’t alone.
Sometimes, writers are the only people they know who willingly sit down at a computer or notebook and spend hours writing. Though writing is a solitary action, it doesn't always need to be. Socializing with people who do the same thing can be incredibly fulfilling. A writing community is a group of people going through the same process and struggles as you.
2. People write many different things, for different reasons.
It's interesting when a writing group gets together because it's likely they all write different genres or types of work. You might meet someone who writes solely romantic novels while you write memoirs, but you're still going to have a lot in common.
3. There's a lot to learn from other writers.
Joining a critique group requires throwing your ego and defenses into a fire. Whether you're experienced or inexperienced in critiquing your own writing, there will be always something about your writing that requires another set of eyes. If someone wants to be published, they will need to develop a hard shell in order to withstand the pressure that comes with criticism, submitting work, and rejection letters. Getting into the habit of critiquing well and thoroughly can develop your writing and editing skills.
There are also plenty of other things to learn, just from talking about writing in general. If you're completely lost as to how to go about writing or plotting, a writing group can tell you about their own process and the ultimate truth: everyone does it their own way, and no one knows exactly what they're doing.
4. Writers like you can actually get published.
Sometimes a writer will mention they're published, and a hushed awe falls over the entire group. Published authors can seem mythical, even nonexistent, but they're out there and they live among us. The unpublished writers can be like them too, some day.
5. A writing community is the best cheering squad.
Writing communities are the actual best places to find friends. Even if you only end up being acquaintances with most of them, that group of people can be your support and cheering squad through every step of the writing process.
6. Your productivity actually increases when you join a community.
When going to write-ins (in which people literally just sit and write in each other's company), they often worry that they won't actually get any writing done. The opposite is usually true. When I write alone, I can usually only get out 500-1000 words in one sitting but when I go to a write-in, 3,000 words comes easy. When a group of writers gets together for the purpose of making words, it's like they form this collective creative aura that naturally encourages and inspires writing.
If you have no idea where to find such a writing community and don't know any writers locally, try checking or joining websites such as Scribophile.com and Meetup.com. Also, local colleges and universities often have related clubs and events, and some of them are open to the public. At any time of the year, you can go to NaNoWriMo.org, look for your home region's page, and that group will often have its own Facebook group where they list events and meetups year-round.