Hobbies are fun. They're what you choose to do when you don't have anything you have to do. But when you make the leap to indie author, writing is no longer your hobby. It's not your job (in most cases, it's only one of the jobs you have). And to be good at it, you have to learn how to sacrifice.
Your Books, Yourself
When you work all day at a job, and I'm going to go ahead and assume that you don't get to write novels all day at your job, you're going to be tired when it's finally over. You might be frustrated, grumpy, all sorts of stuff. You might be looking forward to some relaxation time, maybe doing a little unwinding with some video games or a movie.
Forget it. If you're an indie author, your second work day just begins when the regular work day ends. You can't play games or watch a movie, because you have plots to imagine and pages to type and paragraphs to edit -- so get to it.
And when the weekend rolls around? Well, you worked all week at your job-job and you worked on your book in your spare time. So clearly Saturday is a great time to sleep in, maybe enjoy a round of golf with the guys or a day of shopping with the girls (or vice versa, because there are no sexists here). Nope. The weekends give you the chance to really get some work done on your books, uninterrupted time that you don't have to snatch here and there. So close the windows, shut the door and start typing.
Just when you think you might be able to snag some time off, that's about the time you're going to have to answer your author emails, maybe write some tweets. You need to post on your blog, get active on Facebook and catch up to the forums you've been neglecting. In other words, there goes your Sunday, too. You'll need that whole day just to catch up to your responsibilities, and it's very likely you'll fall into some sort of sleep coma for a few hours.
If you work full-time and keep up any sort of grooming routine, and eat and sleep on top of it, there's no way around it: you have to make sacrifices to be an indie author. You have to be promoting daily to sell books and you've got to work on new projects constantly to keep readers engaged. It's a lot of work, and that means you have to pass up on fun events, free time and stuff in general that you want to do.
But you can't pass all the time, no matter how full your plate may be. If you don't spend some time relaxing and take a few moments to yourself, you won't be able to write at your best. Sacrifice, but don't completely deprive yourself. Work, but don't over-burden yourself daily. Be disciplined, but not unreasonable. It's hard to find the right balance, but it's easier when you know what it takes to be an indie author.