I, like many other people, got the annoying glitch that I cannot become the Thane of Riften. After moping around for a bit and letting out my dark side by doing Daedric Quests, I return to Maven Black-Briar, and, in a moment of supreme fury, slash her with the mace of Molag Bal. She is immortal, and just staggers around. But even though she was in a room filled with guards, no one gave me a second glance. I even killed a Imperial Guard stationed there and no one turned a hair.
People, frusterated by the Jarl and any other NPCs in your way, I would encourage you to let out your fury on those who deserve it. And increase your Blade skill at the same time. Any other glitches that conveniently play into Revenge??