Some rules are meant to be followed, others to be bent/ignored, and some are just bullshit. Figuring out which is which, now that's the damn challenge.
Don't use adverbs. Don't swear. Don't head hop. Don't write about vampires anymore. Do write about angels, merman, sprites with kites, or whatever other bullshit faerie creature's hot atm. Do write XX,XXX words for XX genre. Do omit needless words... good luck figuring that out. Do start in media res. Don't start waking up (The Road, The Hunger Games), Don't do prologues...
After awhile, there are enough rules that the box/prison is clearly defined. If you haven't checked out Michelle Argyle's recent post, I'd highly recommend it, because the video she links to captures what's wrong with rules far better than I can.
Doesn't mean we should shun all rules (that 400k novel's not gonna sell for an FTA), but don't let creativity be stymied by others, otherwise the artistic process can become a stressful chore... and then why do it anymore?