1. It's time-consuming. Ridiculously, tremendously time-consuming. It's so time-consuming that you never update your blog, you begin to rationalize your haven't-been-mopped-in-2-months floors as being "immunity boosting", and you start to rock yourself and hum the opening lines of Rent's "Seasons of Love" every time you see a clock or calendar.
2. It's creepy. You begin to categorize friends, family members, acquaintances, and strangers according to their inspiration potential for characters in your novel. You contemplate using one of your secret Pinterest boards to pin photos of your neighbor since he/she has that perfect "weathered" look that you imagine for your heroine's friend's mother's veterinarian.
3. It's mentally overwhelming. Being a writer takes up a lot of thought time and brain-room. You'll show up half-an-hour late to work meetings, forget when you last washed your hair, fail to remember the names of real people (since you're too preoccupied trying to think of the perfect name for your villain), and likely will start pacing while muttering and mumbling to yourself like Gaius Baltar from Battlestar Galactica.
4. It's painful. Consider: Staring at a computer screen and thumbing through how-to books late at night will give you a headache. Fighting with yourself over plot devices, settings, overarching themes, and character arcs will give you a headache. Attempting to go about your day to day life with an entire world stuck in your head will.give.you.a.headache.
5. It's scary. It might seem intimidating to actually announce your goal of writing a book. It's even more frightening to think about trying to write a book and failing. A gazillion unnerving questions will continuously taunt you. "What if my writing sucks? What if I never finish writing this book? What if my story never gets published? What if it gets published and everyone hates it? What if I'm just not cut out for this?" Being a writer means embracing the potential to fail. It means doing your best and acknowledging that you might not be good enough.
So if you're thinking of being a writer, be forewarned. And if, like me, you decide to ignore the warnings, then I have one piece of advice for you:
Don't give up.