There are SO many writing rules, but sometimes we have to break one or two, just to keep things interesting. Is there a writing rule you've broken on purpose? Why did you choose to break it? And if you want to post a snippet of your writing as an example, even better!
Although I'm very picky about grammar, even I break the rules occasionally. One rule that I've broken on purpose is the rule against sentence fragments. I've done so as a way of emphasizing items and to increase tension. Here's an example where I wrote a paragraph of fragments. It's taken from my Beatles fanfiction story "The Movement You Need." In this story, Paul has found a strange guitar in his bed and is searching his hotel room, trying to figure out how it got there:
Paul doubled up the belt in his left hand. He glanced around, but there was no place to hide in the room except for the closet. Silently, he padded over to the closet door and raised his belt. He yanked the closet door open –
Shirts and slacks, neatly hung on the hangers provided by the hotel. His suitcase on the luggage rack, lid open. A couple pairs of non-leather shoes on the floor. Nothing else.
P.S. Something I should have said earlier is that before you can break the rules successfully, you first have to understand and master them. If you break the rule repeatedly out of ignorance, then readers can spot that. However, if you follow the rule 99.9% of the time and then break it at a strategic spot, then it has more impact.